1
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Opačak N, Schneider B, Faist J, Schwarz B. Impact of higher-order dispersion on frequency-modulated combs. Opt Lett 2024; 49:794-797. [PMID: 38359184 DOI: 10.1364/ol.509529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 01/11/2024] [Indexed: 02/17/2024]
Abstract
Frequency-modulated (FM) combs form spontaneously in free-running semiconductor lasers and possess a vast potential for spectroscopic applications. Despite recent progress in obtaining a conclusive theoretical description, experimental FM combs often exhibit non-ideal traits, which prevents their widespread use. Here we explain this by providing a clear theoretical and experimental study of the impact of the higher-order dispersion on FM combs. We reveal that spectrally dependent dispersion is detrimental for comb performance and leads to a decreased comb bandwidth and the appearance of spectral holes. These undesirable traits can be mended by applying a radio frequency modulation of the laser bias. We show that electrical injection-locking of the laser leads to a significant increase of the comb bandwidth, a uniform-like spectral amplitudes, and the rectification of the instantaneous frequency to recover a nearly linear frequency chirp of FM combs.
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2
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Seitner L, Popp J, Heckelmann I, Vass RE, Meng B, Haider M, Faist J, Jirauschek C. Backscattering-Induced Dissipative Solitons in Ring Quantum Cascade Lasers. Phys Rev Lett 2024; 132:043805. [PMID: 38335338 DOI: 10.1103/physrevlett.132.043805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 10/25/2023] [Accepted: 11/27/2023] [Indexed: 02/12/2024]
Abstract
Ring quantum cascade lasers have recently gained considerable attention, showing ultrastable frequency comb and soliton operation, thus opening a way to integrated spectrometers in the midinfrared and terahertz fingerprint regions. Thanks to a self-consistent Maxwell-Bloch model, we demonstrate, in excellent agreement with the experimental data, that a small but finite coupling between the counterpropagating waves arising from distributed backscattering is essential to stabilize the soliton solution.
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Affiliation(s)
- Lukas Seitner
- TUM School of Computation, Information and Technology, Technical University of Munich (TUM), 85748 Garching, Germany
| | - Johannes Popp
- TUM School of Computation, Information and Technology, Technical University of Munich (TUM), 85748 Garching, Germany
| | - Ina Heckelmann
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule Zürich, 8092 Zurich, Switzerland
| | - Réka-Eszter Vass
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule Zürich, 8092 Zurich, Switzerland
- Physik-Institut, Universität Zürich, 8057 Zurich, Switzerland
| | - Bo Meng
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule Zürich, 8092 Zurich, Switzerland
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, People's Republic of China
| | - Michael Haider
- TUM School of Computation, Information and Technology, Technical University of Munich (TUM), 85748 Garching, Germany
| | - Jérôme Faist
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule Zürich, 8092 Zurich, Switzerland
| | - Christian Jirauschek
- TUM School of Computation, Information and Technology, Technical University of Munich (TUM), 85748 Garching, Germany
- TUM Center for Quantum Engineering (ZQE), 85748 Garching, Germany
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3
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Heckelmann I, Bertrand M, Dikopoltsev A, Beck M, Scalari G, Faist J. Quantum walk comb in a fast gain laser. Science 2023; 382:434-438. [PMID: 37883562 DOI: 10.1126/science.adj3858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/07/2023] [Indexed: 10/28/2023]
Abstract
Synthetic lattices in photonics enable the exploration of light states in new dimensions, transcending phenomena common only to physical space. We propose and demonstrate a quantum walk comb in synthetic frequency space formed by externally modulating a ring-shaped semiconductor laser with ultrafast recovery times. The initially ballistic quantum walk does not dissipate into low supermode states of the synthetic lattice; instead, the state stabilizes in a broad frequency comb, unlocking the full potential of the synthetic frequency lattice. Our device produces a low-noise, nearly flat broadband comb (reaching 100 per centimeter bandwidth) and offers a promising platform to generate broadband, tunable, and stable frequency combs.
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Affiliation(s)
- Ina Heckelmann
- Institute of Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland, and Quantum Center, ETH Zürich, 8093 Zürich, Switzerland
| | - Mathieu Bertrand
- Institute of Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland, and Quantum Center, ETH Zürich, 8093 Zürich, Switzerland
| | - Alexander Dikopoltsev
- Institute of Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland, and Quantum Center, ETH Zürich, 8093 Zürich, Switzerland
| | - Mattias Beck
- Institute of Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland, and Quantum Center, ETH Zürich, 8093 Zürich, Switzerland
| | - Giacomo Scalari
- Institute of Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland, and Quantum Center, ETH Zürich, 8093 Zürich, Switzerland
| | - Jérôme Faist
- Institute of Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland, and Quantum Center, ETH Zürich, 8093 Zürich, Switzerland
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4
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Micheletti P, Senica U, Forrer A, Cibella S, Torrioli G, Frankié M, Beck M, Faist J, Scalari G. Terahertz optical solitons from dispersion-compensated antenna-coupled planarized ring quantum cascade lasers. Sci Adv 2023; 9:eadf9426. [PMID: 37315137 DOI: 10.1126/sciadv.adf9426] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 05/08/2023] [Indexed: 06/16/2023]
Abstract
Quantum cascade lasers (QCLs) constitute an intriguing opportunity for the generation of on-chip optical dissipative Kerr solitons (DKSs). Originally demonstrated in passive microresonators, DKSs were recently observed in mid-infrared ring QCL paving the way for their achievement even at longer wavelengths. To this end, we realized defect-free terahertz ring QCLs featuring anomalous dispersion leveraging on a technological platform based on waveguide planarization. A concentric coupled waveguide approach is implemented for dispersion compensation, while a passive broadband bullseye antenna improves the device power extraction and far field. Comb spectra featuring sech2 envelopes are presented for free-running operation. The presence of solitons is further supported by observing the highly hysteretic behavior, measuring the phase difference between the modes, and reconstructing the intensity time profile highlighting the presence of self-starting 12-picosecond-long pulses. These observations are in very good agreement with our numeric simulations based on a Complex Ginzburg-Landau Equation (CGLE).
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Affiliation(s)
- Paolo Micheletti
- Institute for Quantum Electronics, ETH-Zürich, 8093 Zürich, Switzerland
| | - Urban Senica
- Institute for Quantum Electronics, ETH-Zürich, 8093 Zürich, Switzerland
| | - Andres Forrer
- Institute for Quantum Electronics, ETH-Zürich, 8093 Zürich, Switzerland
| | - Sara Cibella
- CNR-Istituto di Fotonica e Nanotecnologie, Rome, Italy
| | | | - Martin Frankié
- Institute for Quantum Electronics, ETH-Zürich, 8093 Zürich, Switzerland
| | - Mattias Beck
- Institute for Quantum Electronics, ETH-Zürich, 8093 Zürich, Switzerland
| | - Jérôme Faist
- Institute for Quantum Electronics, ETH-Zürich, 8093 Zürich, Switzerland
| | - Giacomo Scalari
- Institute for Quantum Electronics, ETH-Zürich, 8093 Zürich, Switzerland
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5
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Torrioli G, Forrer A, Beck M, Carelli P, Chiarello F, Faist J, Gaggero A, Giovine E, Martini F, Senica U, Leoni R, Scalari G, Cibella S. THz optical beat-note detection with a fast superconducting hot electron bolometer operating up to 31 GHz. Opt Express 2023; 31:15942-15952. [PMID: 37157684 DOI: 10.1364/oe.481081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We study the performance of a hot-electron bolometer (HEB) operating at THz frequencies based on superconducting niobium nitride films. We report on the voltage response of the detector over a large electrical detection bandwidth carried out with different THz sources. We show that the impulse response of the fully packaged HEB at 7.5 K has a 3 dB cutoff around 2 GHz. Remarkably, detection capability is still observed above 30 GHz in an heterodyne beating experiment using a THz quantum cascade laser frequency comb. Additionally, the HEB sensitivity has been evaluated and an optical noise equivalent power NEP of 0.8 pW/√H z has been measured at 1 MHz.
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6
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Markmann S, Franckié M, Bertrand M, Shahmohammadi M, Forrer A, Jouy P, Beck M, Faist J, Scalari G. Frequency chirped Fourier-Transform spectroscopy. Commun Phys 2023; 6:53. [PMID: 38665410 PMCID: PMC11041810 DOI: 10.1038/s42005-023-01157-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 02/24/2023] [Indexed: 04/28/2024]
Abstract
Fast (sub-second) spectroscopy with high spectral resolution is of vital importance for revealing quantum chemistry kinetics of complex chemical and biological reactions. Fourier transform (FT) spectrometers can achieve high spectral resolution and operate at hundreds of ms time scales in rapid-scan mode. However, the linear translation of a scanning mirror imposes stringent time-resolution limitations to these systems, which makes simultaneous high spectral and temporal resolution very difficult. Here, we demonstrate an FT spectrometer whose operational principle is based on continuous rotational motion of the scanning mirror, effectively decoupling the spectral resolution from the temporal one. Furthermore, we show that such rotational FT spectrometer can perform Mid-IR dual-comb spectroscopy with a single comb source, since the Doppler-shifted version of the comb serves as the second comb. In our realization, we combine the advantages of dual-comb and FT spectroscopy using a single quantum cascade laser frequency comb emitting at 8.2 μm as a light source. Our technique does not require any diffractive or dispersive optical elements and hence preserve the Jacquinot's-, Fellgett's-, and Connes'-advantages of FT spectrometers. By integrating mulitple broadband sources, such system could pave the way for applications where high speed, large optical bandwidth, and high spectral resolution are desired.
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Affiliation(s)
- Sergej Markmann
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, 8093 Zürich, Switzerland
| | - Martin Franckié
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, 8093 Zürich, Switzerland
| | - Mathieu Bertrand
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, 8093 Zürich, Switzerland
| | - Mehran Shahmohammadi
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, 8093 Zürich, Switzerland
| | - Andres Forrer
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, 8093 Zürich, Switzerland
| | - Pierre Jouy
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, 8093 Zürich, Switzerland
| | - Mattias Beck
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, 8093 Zürich, Switzerland
| | - Jérôme Faist
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, 8093 Zürich, Switzerland
| | - Giacomo Scalari
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, 8093 Zürich, Switzerland
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7
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Nataraj A, Tuzson B, Gianella M, Prokhorov I, Li G, Ebert V, Faist J, Emmenegger L. Position-Specific Isotope Analysis of Propane by Mid-IR Laser Absorption Spectroscopy. Anal Chem 2023; 95:5354-5361. [PMID: 36913630 DOI: 10.1021/acs.analchem.2c05489] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
Abstract
Intramolecular or position-specific carbon isotope analysis of propane (13CH3-12CH2-12CH3 and 12CH3-13CH2-12CH3) provides unique insights into its formation mechanism and temperature history. The unambiguous detection of such carbon isotopic distributions with currently established methods is challenging due to the complexity of the technique and the tedious sample preparation. We present a direct and nondestructive analytical technique to quantify the two singly substituted, terminal (13Ct) and central (13Cc), propane isotopomers, based on quantum cascade laser absorption spectroscopy. The required spectral information on the propane isotopomers was first obtained using a high-resolution Fourier-transform infrared (FTIR) spectrometer and then used to select suitable mid-infrared regions with minimal spectral interference to obtain the optimum sensitivity and selectivity. We then measured high-resolution spectra around 1384 cm-1 of both singly substituted isotopomers by mid-IR quantum cascade laser absorption spectroscopy using a Stirling-cooled segmented circular multipass cell (SC-MPC). The spectra of the pure propane isotopomers were acquired at both 300 and 155 K and served as spectral templates to quantify samples with different levels of 13C at the central (c) and terminal (t) positions. A prerequisite for the precision using this reference template fitting method is a good match of amount fraction and pressure between the sample and templates. For samples at natural abundance, we achieved a precision of 0.33 ‰ for δ13Ct and 0.73 ‰ for δ13Cc values within 100 s integration time. This is the first demonstration of site-specific high-precision measurements of isotopically substituted non-methane hydrocarbons using laser absorption spectroscopy. The versatility of this analytical approach may open up new opportunities for the study of isotopic distribution of other organic compounds.
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Affiliation(s)
- Akshay Nataraj
- Laboratory for Air Pollution/Environmental Technology, Empa, 8600 Dübendorf, Switzerland
| | - Béla Tuzson
- Laboratory for Air Pollution/Environmental Technology, Empa, 8600 Dübendorf, Switzerland
| | - Michele Gianella
- Laboratory for Air Pollution/Environmental Technology, Empa, 8600 Dübendorf, Switzerland
| | - Ivan Prokhorov
- Laboratory for Air Pollution/Environmental Technology, Empa, 8600 Dübendorf, Switzerland
| | - Gang Li
- Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany
| | - Volker Ebert
- Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany
| | - Jérôme Faist
- Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland
| | - Lukas Emmenegger
- Laboratory for Air Pollution/Environmental Technology, Empa, 8600 Dübendorf, Switzerland
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8
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Herter A, Shams-Ansari A, Settembrini FF, Warner HK, Faist J, Lončar M, Benea-Chelmus IC. Terahertz waveform synthesis in integrated thin-film lithium niobate platform. Nat Commun 2023; 14:11. [PMID: 36599838 DOI: 10.1038/s41467-022-35517-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 12/07/2022] [Indexed: 01/06/2023] Open
Abstract
Bridging the "terahertz gap" relies upon synthesizing arbitrary waveforms in the terahertz domain enabling applications that require both narrow band sources for sensing and few-cycle drives for classical and quantum objects. However, realization of custom-tailored waveforms needed for these applications is currently hindered due to limited flexibility for optical rectification of femtosecond pulses in bulk crystals. Here, we experimentally demonstrate that thin-film lithium niobate circuits provide a versatile solution for such waveform synthesis by combining the merits of complex integrated architectures, low-loss distribution of pump pulses on-chip, and an efficient optical rectification. Our distributed pulse phase-matching scheme grants shaping the temporal, spectral, phase, amplitude, and farfield characteristics of the emitted terahertz field through designer on-chip components. This strictly circumvents prior limitations caused by the phase-delay mismatch in conventional systems and relaxes the requirement for cumbersome spectral pre-engineering of the pumping light. We propose a toolbox of basic blocks that produce broadband emission up to 680 GHz and far-field amplitudes of a few V m-1 with adaptable phase and coherence properties by using near-infrared pump pulse energies below 100 pJ.
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Affiliation(s)
- Alexa Herter
- ETH Zurich, Institute of Quantum Electronics, Zurich, Switzerland.
| | - Amirhassan Shams-Ansari
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
| | | | - Hana K Warner
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Jérôme Faist
- ETH Zurich, Institute of Quantum Electronics, Zurich, Switzerland
| | - Marko Lončar
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
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9
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Senica U, Forrer A, Olariu T, Micheletti P, Cibella S, Torrioli G, Beck M, Faist J, Scalari G. Planarized THz quantum cascade lasers for broadband coherent photonics. Light Sci Appl 2022; 11:347. [PMID: 36566261 PMCID: PMC9789948 DOI: 10.1038/s41377-022-01058-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 11/04/2022] [Accepted: 11/26/2022] [Indexed: 05/25/2023]
Abstract
Recently, there has been a growing interest in integrated THz photonics for various applications in communications, spectroscopy and sensing. We present a new integrated photonic platform based on active and passive elements integrated in a double-metal, high-confinement waveguide layout planarized with a low-loss polymer. An extended top metallization keeps waveguide losses low while improving dispersion, thermal and RF properties, as it enables to decouple the design of THz and microwave cavities. Free-running on-chip quantum cascade laser combs spanning 800 GHz, harmonic states with over 1.1 THz bandwidth and RF-injected broadband incoherent states spanning over nearly 1.6 THz are observed using a homogeneous quantum-cascade active core. With a strong external RF drive, actively mode-locked pulses as short as 4.4 ps can be produced, as measured by SWIFTS. We demonstrate as well passive waveguides with low insertion loss, enabling the tuning of the laser cavity boundary conditions and the co-integration of active and passive elements on the same THz photonic chip.
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Affiliation(s)
- Urban Senica
- Quantum Optoelectronics Group, Institute of Quantum Electronics, ETH Zürich, 8093, Zürich, Switzerland.
| | - Andres Forrer
- Quantum Optoelectronics Group, Institute of Quantum Electronics, ETH Zürich, 8093, Zürich, Switzerland
| | - Tudor Olariu
- Quantum Optoelectronics Group, Institute of Quantum Electronics, ETH Zürich, 8093, Zürich, Switzerland
| | - Paolo Micheletti
- Quantum Optoelectronics Group, Institute of Quantum Electronics, ETH Zürich, 8093, Zürich, Switzerland
| | - Sara Cibella
- Istituto di Fotonica e Nanotecnologie, CNR, Via del Fosso del Cavaliere 100, 00133, Rome, Italy
| | - Guido Torrioli
- Istituto di Fotonica e Nanotecnologie, CNR, Via del Fosso del Cavaliere 100, 00133, Rome, Italy
| | - Mattias Beck
- Quantum Optoelectronics Group, Institute of Quantum Electronics, ETH Zürich, 8093, Zürich, Switzerland
| | - Jérôme Faist
- Quantum Optoelectronics Group, Institute of Quantum Electronics, ETH Zürich, 8093, Zürich, Switzerland
| | - Giacomo Scalari
- Quantum Optoelectronics Group, Institute of Quantum Electronics, ETH Zürich, 8093, Zürich, Switzerland.
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10
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Hillbrand J, Bertrand M, Wittwer V, Opačak N, Kapsalidis F, Gianella M, Emmenegger L, Schwarz B, Südmeyer T, Beck M, Faist J. Synchronization of frequency combs by optical injection. Opt Express 2022; 30:36087-36095. [PMID: 36258545 DOI: 10.1364/oe.456775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 08/24/2022] [Indexed: 06/16/2023]
Abstract
Optical frequency combs based on semiconductor lasers are a promising technology for monolithic integration of dual-comb spectrometers. However, the stabilization of offset frequency fceo remains a challenging feat due the lack of octave-spanning spectra. In a dual-comb configuration, the uncorrelated jitter of the offset frequencies leads to a non-periodic signal resulting in broadened beatnotes with a limited signal-to-noise ratio (SNR). Hence, expensive data acquisition schemes and complex signal processing are currently required. Here, we show that the offset frequencies of two frequency combs can be synchronized by optical injection locking, which allows full phase-stabilization when combined with electrical injection locking of both repetition frequencies frep. A single comb line isolated via an optical Vernier filter serves as Master oscillator for injection locking. The resulting dual-comb signal is periodic and stable over thousands of periods. This enables coherent averaging using analog electronics, which increases the SNR and reduces the data size by one and three orders of magnitude, respectively. The presented method will enable fully phase-stabilized dual-comb spectrometers by leveraging on integrated optical filters and provides access for comparing and stabilizing fceo to narrow-linewidth optical references.
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11
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Settembrini FF, Lindel F, Herter AM, Buhmann SY, Faist J. Detection of quantum-vacuum field correlations outside the light cone. Nat Commun 2022; 13:3383. [PMID: 35697669 PMCID: PMC9192708 DOI: 10.1038/s41467-022-31081-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 06/01/2022] [Indexed: 11/10/2022] Open
Abstract
According to quantum field theory, empty space-the ground state with all real excitations removed-is not empty, but filled with quantum-vacuum fluctuations. Their presence can manifest itself through phenomena such as the Casimir force, spontaneous emission, or dispersion forces. These fluctuating fields possess correlations between space-time points outside the light cone, i.e. points causally disconnected according to special relativity. As a consequence, two initially uncorrelated quantum objects in empty space which are located in causally disconnected space-time regions, and therefore unable to exchange information, can become correlated. Here, we have experimentally demonstrated the existence of correlations of the vacuum fields for non-causally connected space-time points by using electro-optic sampling. This result is obtained by detecting vacuum-induced correlations between two 195 fs laser pulses separated by a time of flight of 470 fs. This work marks a first step in analyzing the space-time structure of vacuum correlations in quantum field theory.
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Affiliation(s)
| | - Frieder Lindel
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany.
| | - Alexa Marina Herter
- ETH Zurich, Institute of Quantum Electronics, Auguste-Piccard-Hof 1, 8093, Zurich, Switzerland
| | - Stefan Yoshi Buhmann
- Institut für Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
| | - Jérôme Faist
- ETH Zurich, Institute of Quantum Electronics, Auguste-Piccard-Hof 1, 8093, Zurich, Switzerland.
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12
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Komagata KN, Gianella M, Jouy P, Kapsalidis F, Shahmohammadi M, Beck M, Matthey R, Wittwer VJ, Hugi A, Faist J, Emmenegger L, Südmeyer T, Schilt S. Absolute frequency referencing in the long wave infrared using a quantum cascade laser frequency comb. Opt Express 2022; 30:12891-12901. [PMID: 35472915 DOI: 10.1364/oe.447650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
Optical frequency combs (OFCs) based on quantum cascade lasers (QCLs) have transformed mid-infrared spectroscopy. However, QCL-OFCs have not yet been exploited to provide a broadband absolute frequency reference. We demonstrate this possibility by performing comb-calibrated spectroscopy at 7.7 µm (1305 cm-1) using a QCL-OFC referenced to a molecular transition. We obtain 1.5·10-10 relative frequency stability (100-s integration time) and 3·10-9 relative frequency accuracy, comparable with state-of-the-art solutions relying on nonlinear frequency conversion. We show that QCL-OFCs can be locked with sub-Hz-level stability to a reference for hours, thus promising their use as metrological tools for the mid-infrared.
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13
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Casamenti E, Torun G, Borasi L, Lautenbacher M, Bertrand M, Faist J, Mortensen A, Bellouard Y. Glass-in-glass infiltration for 3D micro-optical composite components. Opt Express 2022; 30:13603-13615. [PMID: 35472970 DOI: 10.1364/oe.451026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
Chalcogenide glass exhibits a wide transmission window in the infrared range, a high refractive index, and nonlinear optical properties; however, due to its poor mechanical properties and low chemical and environmental stability, producing three-dimensional microstructures of chalcogenide glass remains a challenge. Here, we combine the fabrication of arbitrarily shaped three-dimensional cavities within fused silica molds by means of femtosecond laser-assisted chemical etching with the pressure-assisted infiltration of a chalcogenide glass into the resulting carved silica mold structures. This process enables the fabrication of 3D, geometrically complex, chalcogenide-silica micro-glass composites. The resulting products feature a high refractive index contrast that enables total-internal-reflection guiding and an optical quality roughness level suited for applications in the infrared.
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14
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Appugliese F, Enkner J, Paravicini-Bagliani GL, Beck M, Reichl C, Wegscheider W, Scalari G, Ciuti C, Faist J. Breakdown of topological protection by cavity vacuum fields in the integer quantum Hall effect. Science 2022; 375:1030-1034. [PMID: 35239382 DOI: 10.1126/science.abl5818] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The prospect of controlling the electronic properties of materials via the vacuum fields of cavity electromagnetic resonators is emerging as one of the frontiers of condensed matter physics. We found that the enhancement of vacuum field fluctuations in subwavelength split-ring resonators strongly affects one of the most paradigmatic quantum protectorates, the quantum Hall electron transport in high-mobility two-dimensional electron gases. The observed breakdown of the topological protection of the integer quantum Hall effect is interpreted in terms of a long-range cavity-mediated electron hopping where the anti-resonant terms of the light-matter coupling Hamiltonian develop into a finite resistivity induced by the vacuum fluctuations. Our experimental platform can be used for any two-dimensional material and provides a route to manipulate electron phases in matter by means of vacuum-field engineering.
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Affiliation(s)
- Felice Appugliese
- Institute of Quantum Electronics, ETH Zürich, Zürich 8093, Switzerland
| | - Josefine Enkner
- Institute of Quantum Electronics, ETH Zürich, Zürich 8093, Switzerland
| | | | - Mattias Beck
- Institute of Quantum Electronics, ETH Zürich, Zürich 8093, Switzerland
| | - Christian Reichl
- Laboratory for Solid State Physics, ETH Zürich, Zürich 8093, Switzerland
| | - Werner Wegscheider
- Laboratory for Solid State Physics, ETH Zürich, Zürich 8093, Switzerland
| | - Giacomo Scalari
- Institute of Quantum Electronics, ETH Zürich, Zürich 8093, Switzerland
| | - Cristiano Ciuti
- CNRS, Laboratoire Matériaux et Phénomènes Quantiques, Université de Paris, F-75013 Paris, France
| | - Jérôme Faist
- Institute of Quantum Electronics, ETH Zürich, Zürich 8093, Switzerland
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15
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Gianella M, Vogel S, Wittwer VJ, Südmeyer T, Faist J, Emmenegger L. Frequency axis for swept dual-comb spectroscopy with quantum cascade lasers. Opt Lett 2022; 47:625-628. [PMID: 35103695 DOI: 10.1364/ol.446347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
In dual-comb spectroscopy, there is a one-to-one map between the frequencies of the measured beat notes and the frequencies of the optical comb lines. Its determination usually involves the use of one or more reference lasers with known frequencies. Quantum cascade laser frequency combs, however, are often operated in a free-running mode, and without a reference, the determination of the RF-to-optical frequency map is not trivial. Here, we propose a method by which the comb shift is measured with an unbalanced Mach-Zehnder interferometer, and the spectral point spacing is determined through the intermode beat measured on the laser electrodes. The frequency axis is accurate within ∼ 0.001 cm-1.
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16
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Nataraj A, Gianella M, Prokhorov I, Tuzson B, Bertrand M, Mohn J, Faist J, Emmenegger L. Quantum cascade laser absorption spectrometer with a low temperature multipass cell for precision clumped CO 2 measurement. Opt Express 2022; 30:4631-4641. [PMID: 35209695 DOI: 10.1364/oe.447172] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/10/2021] [Indexed: 06/14/2023]
Abstract
We present a quantum cascade laser-based absorption spectrometer deploying a compact (145 mL volume) segmented circular multipass cell (SC-MPC) with 6 m optical path length. This SC-MPC is embedded into an effective cooling system to facilitate operation at cryogenic temperatures. For CO2, the sample is cooled to 153 K, i.e. close to the sublimation point at 10 mbar. This enables efficient suppression of interfering hot-band transitions of the more abundant isotopic species and thereby enhances analytical precision. As a demonstration, the amount fractions of all three CO2 isotopologues involved in the kinetic isotope exchange reaction of 12C16O2 + 12C18O2⇌ 2·12C16O18O are measured. The precision in the ratios [12C18O2]/[12C16O2] and [12C16O18O]/[12C16O2] is 0.05 ‰ with 25 s integration time. In addition, we determine the variation of the equilibrium constant, K, of the above exchange reaction for carbon-dioxide samples equilibrated at 300 K and 1273 K, respectively.
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17
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Scalari G, Rajabali S, Jöchl E, Markmann S, de Liberato S, Cortese E, Beck M, Faist J. Non-locality and single meta-atom spectroscopy in THz Landau polaritons. EPJ Web Conf 2022. [DOI: 10.1051/epjconf/202226608013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We will discuss, theoretically and experimentally, the existence of a limit to the possibility of arbitrarily increasing electromagnetic confinement in polaritonic systems, where strongly sub-wavelength fields can excite a continuum of high-momenta propagative magnetoplasmons. This leads to peculiar nonlocal polaritonic effects, as certain polaritonic features disappear and the system enters in the regime of discrete-to-continuum strong coupling. We will as well present experiments reporting spectroscopy of a single, ultrastrongly coupled, highly subwavelength resonator operating at 300 GHz.
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18
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Täschler P, Bertrand M, Schneider B, Singleton M, Jouy P, Kapsalidis F, Beck M, Faist J. Femtosecond pulses from a mid-infrared quantum cascade laser. Nat Photonics 2021; 15:919-924. [PMID: 34899974 PMCID: PMC8629755 DOI: 10.1038/s41566-021-00894-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 09/16/2021] [Indexed: 06/14/2023]
Abstract
The quantum cascade laser has evolved to be a compact, powerful source of coherent mid-infrared light; however, its fast gain dynamics strongly restricts the formation of ultrashort pulses. As such, the shortest pulses reported so far were limited to a few picoseconds with some hundreds of milliwatts of peak power, strongly narrowing their applicability for time-resolved and nonlinear experiments. Here we demonstrate an approach capable of producing near-transform-limited subpicosecond pulses with several watts of peak power. Starting from a frequency-modulated phase-locked state, ultrashort high-peak-power pulses are generated via spectral filtering, gain modulation-induced spectral broadening and external pulse compression. We assess their temporal nature by means of a novel asynchronous sampling method, coherent beat note interferometry and interferometric autocorrelation. These results open new pathways for nonlinear physics in the mid-infrared.
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Affiliation(s)
- Philipp Täschler
- Institute for Quantum Electronics, ETH Zurich, Zurich, Switzerland
| | - Mathieu Bertrand
- Institute for Quantum Electronics, ETH Zurich, Zurich, Switzerland
| | | | | | - Pierre Jouy
- Institute for Quantum Electronics, ETH Zurich, Zurich, Switzerland
| | | | - Mattias Beck
- Institute for Quantum Electronics, ETH Zurich, Zurich, Switzerland
| | - Jérôme Faist
- Institute for Quantum Electronics, ETH Zurich, Zurich, Switzerland
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19
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Husmann D, Bernier LG, Bertrand M, Calonico D, Chaloulos K, Clausen G, Clivati C, Faist J, Heiri E, Hollenstein U, Johnson A, Mauchle F, Meir Z, Merkt F, Mura A, Scalari G, Scheidegger S, Schmutz H, Sinhal M, Willitsch S, Morel J. SI-traceable frequency dissemination at 1572.06 nm in a stabilized fiber network with ring topology. Opt Express 2021; 29:24592-24605. [PMID: 34614812 DOI: 10.1364/oe.427921] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 07/03/2021] [Indexed: 06/13/2023]
Abstract
Frequency dissemination in phase-stabilized optical fiber networks for metrological frequency comparisons and precision measurements are promising candidates to overcome the limitations imposed by satellite techniques. However, in an architecture shared with telecommunication data traffic, network constraints restrict the availability of dedicated channels in the commonly-used C-band. Here, we demonstrate the dissemination of an SI-traceable ultrastable optical frequency in the L-band over a 456 km fiber network with ring topology, in which data traffic occupies the full C-band. We characterize the optical phase noise and evaluate a link instability of 4.7 × 10-16 at 1 s and 3.8 × 10-19 at 2000 s integration time, and a link accuracy of 2 × 10-18. We demonstrate the application of the disseminated frequency by establishing the SI-traceability of a laser in a remote laboratory. Finally, we show that our metrological frequency does not interfere with data traffic in the telecommunication channels. Our approach combines an unconventional spectral choice in the telecommunication L-band with established frequency-stabilization techniques, providing a novel, cost-effective solution for ultrastable frequency-comparison and dissemination, and may contribute to a foundation of a world-wide metrological network.
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20
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Komagata K, Shehzad A, Terrasanta G, Brochard P, Matthey R, Gianella M, Jouy P, Kapsalidis F, Shahmohammadi M, Beck M, Wittwer VJ, Faist J, Emmenegger L, Südmeyer T, Hugi A, Schilt S. Coherently-averaged dual comb spectrometer at 7.7 µm with master and follower quantum cascade lasers. Opt Express 2021; 29:19126-19139. [PMID: 34154154 DOI: 10.1364/oe.425480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 05/18/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate coherent averaging of the multi-heterodyne beat signal between two quantum cascade laser frequency combs in a master-follower configuration. The two combs are mutually locked by acting on the drive current to control their relative offset frequency and by radio-frequency extraction and injection locking of their intermode beat signal to stabilize their mode spacing difference. By implementing an analog common-noise subtraction scheme, a reduction of the linewidth of all heterodyne beat notes by five orders of magnitude is achieved compared to the free-running lasers. We compare stabilization and post-processing corrections in terms of amplitude noise. While they give similar performances in terms of signal-to-noise ratio, real-time processing of the stabilized signal is less demanding in terms of computational power. Lastly, a proof-of-principle spectroscopic measurement was performed, showing the possibility to reduce the amount of data to be processed by three orders of magnitude, compared to the free-running system.
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21
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Wang R, Täschler P, Kapsalidis F, Shahmohammadi M, Beck M, Faist J. Mid-infrared quantum cascade laser frequency combs based on multi-section waveguides. Opt Lett 2020; 45:6462-6465. [PMID: 33258837 DOI: 10.1364/ol.411027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 10/25/2020] [Indexed: 06/12/2023]
Abstract
We present quantum cascade laser (QCL) frequency comb devices with engineered waveguides for managing the dispersion. The QCL waveguide consists of multiple sections with different waveguide widths. The narrow and wide sections of the waveguide are designed in a way to compensate the group velocity dispersion (GVD) of each other and thereby produce a flat and slightly negative GVD for the QCL. The QCL exhibits continuous comb operation over a large part of the dynamic range of the laser. Strong and narrow-linewidth intermode beatnotes are achieved in a more than 300 mA wide operation current range. The comb device also features considerably high output power (>380mW) and wide optical bandwidth (>55cm-1).
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22
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Shehzad A, Brochard P, Matthey R, Kapsalidis F, Shahmohammadi M, Beck M, Hugi A, Jouy P, Faist J, Südmeyer T, Schilt S. Frequency noise correlation between the offset frequency and the mode spacing in a mid-infrared quantum cascade laser frequency comb. Opt Express 2020; 28:8200-8210. [PMID: 32225449 DOI: 10.1364/oe.385849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
The generation of frequency combs in the mid-infrared (MIR) spectral range by quantum cascade lasers (QCLs) has the potential for revolutionizing dual-comb multi-heterodyne spectroscopy in the molecular fingerprint region. However, in contrast to frequency combs based on passively mode-locked ultrafast lasers, their operation relies on a completely different mechanism resulting from a four-wave mixing process occurring in the semiconductor gain medium that locks the modes together. As a result, these lasers do not emit pulses and no direct self-referencing of a QCL comb spectrum has been achieved so far. Here, we present a detailed frequency noise characterization of a MIR QCL frequency comb operating at a wavelength of 8 µm with a mode spacing of ∼7.4 GHz. Using a beat measurement with a narrow-linewidth single-mode QCL in combination with a dedicated electrical scheme, we measured the frequency noise properties of an optical mode of the QCL comb, and indirectly of its offset frequency for the first time, without detecting it by the standard approach of nonlinear interferometry applied to ultrafast mode-locked lasers. In addition, we also separately measured the noise of the comb mode spacing extracted electrically from the QCL. We observed a strong anti-correlation between the frequency fluctuations of the offset frequency and mode spacing, leading to optical modes with a linewidth slightly below 1 MHz in the free-running QCL comb (at 1-s integration time), which is narrower than the individual contributions of the offset frequency and mode spacing that are at least 2 MHz each.
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23
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Gianella M, Nataraj A, Tuzson B, Jouy P, Kapsalidis F, Beck M, Mangold M, Hugi A, Faist J, Emmenegger L. High-resolution and gapless dual comb spectroscopy with current-tuned quantum cascade lasers. Opt Express 2020; 28:6197-6208. [PMID: 32225874 DOI: 10.1364/oe.379790] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/06/2020] [Indexed: 06/10/2023]
Abstract
We present gapless, high-resolution absorption and dispersion spectra obtained with quantum cascade laser frequency combs covering 55 cm-1. Using phase-sensitive dual comb design, the comb lines are gradually swept over 10 GHz, corresponding to the free spectral range of the laser devices, by applying a current modulation. We show that with interleaving the spectral point spacing is reduced by more than four orders of magnitude over the full spectral span of the frequency comb. The potential of this technique for high-precision gas sensing is illustrated by measuring the low pressure (107 hPa) absorption and dispersion spectra of methane spanning the range of 1170 cm-1 - 1225 cm-1 with a resolution of 0.001 cm-1.
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24
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Gallacher K, Ortolani M, Rew K, Ciano C, Baldassarre L, Virgilio M, Scalari G, Faist J, Di Gaspare L, De Seta M, Capellini G, Grange T, Birner S, Paul DJ. Design and simulation of losses in Ge/SiGe terahertz quantum cascade laser waveguides. Opt Express 2020; 28:4786-4800. [PMID: 32121710 DOI: 10.1364/oe.384993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 01/24/2020] [Indexed: 06/10/2023]
Abstract
The waveguide losses from a range of surface plasmon and double metal waveguides for Ge/Si1-xGex THz quantum cascade laser gain media are investigated at 4.79 THz (62.6 μm wavelength). Double metal waveguides demonstrate lower losses than surface plasmonic guiding with minimum losses for a 10 μm thick active gain region with silver metal of 21 cm-1 at 300 K reducing to 14.5 cm-1 at 10 K. Losses for silicon foundry compatible metals including Al and Cu are also provided for comparison and to provide a guide for gain requirements to enable lasers to be fabricated in commercial silicon foundries. To allow these losses to be calculated for a range of designs, the complex refractive index of a range of nominally undoped Si1-xGex with x = 0.7, 0.8 and 0.9 and doped Ge heterolayers were extracted from Fourier transform infrared spectroscopy measurements between 0.1 and 10 THz and from 300 K down to 10 K. The results demonstrate losses comparable to similar designs of GaAs/AlGaAs quantum cascade laser plasmon waveguides indicating that a gain threshold of 15.1 cm-1 and 23.8 cm-1 are required to produce a 4.79 THz Ge/SiGe THz laser at 10 K and 300 K, respectively, for 2 mm long double metal waveguide quantum cascade lasers with facet coatings.
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25
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Salamin Y, Benea-Chelmus IC, Fedoryshyn Y, Heni W, Elder DL, Dalton LR, Faist J, Leuthold J. Compact and ultra-efficient broadband plasmonic terahertz field detector. Nat Commun 2019; 10:5550. [PMID: 31804476 PMCID: PMC6895079 DOI: 10.1038/s41467-019-13490-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 11/04/2019] [Indexed: 11/22/2022] Open
Abstract
Terahertz sources and detectors have enabled numerous new applications from medical to communications. Yet, most efficient terahertz detection schemes rely on complex free-space optics and typically require high-power lasers as local oscillators. Here, we demonstrate a fiber-coupled, monolithic plasmonic terahertz field detector on a silicon-photonics platform featuring a detection bandwidth of 2.5 THz with a 65 dB dynamical range. The terahertz wave is measured through its nonlinear mixing with an optical probe pulse with an average power of only 63 nW. The high efficiency of the scheme relies on the extreme confinement of the terahertz field to a small volume of 10−8(λTHz/2)3. Additionally, on-chip guided plasmonic probe beams sample the terahertz signal efficiently in this volume. The approach results in an extremely short interaction length of only 5 μm, which eliminates the need for phase matching and shows the highest conversion efficiency per unit length up to date. Most efficient terahertz detection schemes rely on complex free space optics and require high-power lasers. Here, the authors report an integrated plasmonic terahertz detector on a silicon photonics platform, with 2.5 THz bandwidth and a 65 dB dynamical range operating at an optical power of only 63 nW.
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Affiliation(s)
- Yannick Salamin
- ETH Zurich, Institute of Electromagnetic Fields (IEF), 8092, Zurich, Switzerland.
| | - Ileana-Cristina Benea-Chelmus
- ETH Zurich, Institute for Quantum Electronics (IQE), 8093, Zurich, Switzerland. .,Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA.
| | - Yuriy Fedoryshyn
- ETH Zurich, Institute of Electromagnetic Fields (IEF), 8092, Zurich, Switzerland
| | - Wolfgang Heni
- ETH Zurich, Institute of Electromagnetic Fields (IEF), 8092, Zurich, Switzerland
| | - Delwin L Elder
- Department of Chemistry, University of Washington, Seattle, WA, 98195-1700, USA
| | - Larry R Dalton
- Department of Chemistry, University of Washington, Seattle, WA, 98195-1700, USA
| | - Jérôme Faist
- ETH Zurich, Institute for Quantum Electronics (IQE), 8093, Zurich, Switzerland
| | - Juerg Leuthold
- ETH Zurich, Institute of Electromagnetic Fields (IEF), 8092, Zurich, Switzerland.
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26
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Wang Z, Liang Y, Meng B, Sun YT, Omanakuttan G, Gini E, Beck M, Sergachev I, Lourdudoss S, Faist J, Scalari G. Large area photonic crystal quantum cascade laser with 5 W surface-emitting power. Opt Express 2019; 27:22708-22716. [PMID: 31510557 DOI: 10.1364/oe.27.022708] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 07/09/2019] [Indexed: 06/10/2023]
Abstract
Room temperature surface emission is realized on a large area (1.5 mm × 1.5 mm) photonic crystal quantum cascade laser (PhC-QCL) driven under pulsed mode, at the wavelength around 8.75 μm. By introducing in-plane asymmetry to the pillar shape and optimizing the current injection with a grid-like window contact, the maximum peak power of the PhC-QCL is up to 5 W. The surface emitting beam has a crossing shape with 10° divergence.
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27
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Ohtani K, Meng B, Franckié M, Bosco L, Ndebeka-Bandou C, Beck M, Faist J. An electrically pumped phonon-polariton laser. Sci Adv 2019; 5:eaau1632. [PMID: 31309138 PMCID: PMC6625821 DOI: 10.1126/sciadv.aau1632] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 06/05/2019] [Indexed: 05/28/2023]
Abstract
We report a device that provides coherent emission of phonon polaritons, a mixed state between photons and optical phonons in an ionic crystal. An electrically pumped GaInAs/AlInAs quantum cascade structure provides intersubband gain into the polariton mode at λ = 26.3 μm, allowing self-oscillations close to the longitudinal optical phonon energy of AlAs. Because of the large computed phonon fraction of the polariton of 65%, the emission appears directly on a Raman spectrum measurement, exhibiting a Stokes and anti-Stokes component with the expected shift of 48 meV.
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Affiliation(s)
- Keita Ohtani
- Institute for Quantum Electronics, ETH Zürich, August-Piccard-Hof 1, 8093 Zurich, Switzerland
| | - Bo Meng
- Institute for Quantum Electronics, ETH Zürich, August-Piccard-Hof 1, 8093 Zurich, Switzerland
| | - Martin Franckié
- Institute for Quantum Electronics, ETH Zürich, August-Piccard-Hof 1, 8093 Zurich, Switzerland
| | - Lorenzo Bosco
- Institute for Quantum Electronics, ETH Zürich, August-Piccard-Hof 1, 8093 Zurich, Switzerland
| | - Camille Ndebeka-Bandou
- Institute for Quantum Electronics, ETH Zürich, August-Piccard-Hof 1, 8093 Zurich, Switzerland
| | - Mattias Beck
- Institute for Quantum Electronics, ETH Zürich, August-Piccard-Hof 1, 8093 Zurich, Switzerland
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28
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Westberg J, Sterczewski LA, Kapsalidis F, Bidaux Y, Wolf JM, Beck M, Faist J, Wysocki G. Dual-comb spectroscopy using plasmon-enhanced-waveguide dispersion-compensated quantum cascade lasers. Opt Lett 2018; 43:4522-4525. [PMID: 30211906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this Letter, we report on sub-millisecond response time mid-infrared dual-comb spectroscopy using a balanced asymmetric (dispersive) dual-comb setup with a matched pair of plasmon-enhanced-waveguide dispersion-compensated quantum cascade lasers. The system performance is demonstrated by measuring spectra of Bromomethane (CH3Br) and Freon 134a (CH2FCF3) at approximately 7.8 μm. A purely computational phase and timing-correction procedure is used to validate the coherence of the quantum cascade lasers frequency combs and to enable coherent averaging over the time scales investigated. The system achieves a noise-equivalent absorption better than 1×10-3 Hz-1/2, with a resolution of 9.8 GHz (0.326 cm-1) and an optical bandwidth of 1 THz (32 cm-1), with an average optical power of more than 1 mW per spectral element.
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29
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Forrer A, Rösch M, Singleton M, Beck M, Faist J, Scalari G. Coexisting frequency combs spaced by an octave in a monolithic quantum cascade laser. Opt Express 2018; 26:23167-23177. [PMID: 30184971 DOI: 10.1364/oe.26.023167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/05/2018] [Indexed: 06/08/2023]
Abstract
Quantum cascade lasers are proving to be instrumental in the development of compact frequency comb sources at mid-infrared and terahertz frequencies. Here we demonstrate a heterogeneous terahertz quantum cascade laser with two active regions spaced exactly by one octave. Both active regions are based on a four-quantum well laser design and they emit a combined 3 mW peak power at 15 K in pulsed mode. The two central frequencies are 2.3 THz (bandwidth 300 GHz) and 4.6 THz (bandwidth 270 GHz). The structure is engineered in a way that allows simultaneous operation of the two active regions in the comb regime, serving as a double comb source as well as a test bench structure for all waveguide internal self-referencing techniques. Narrow RF beatnotes (∼ 15 kHz) are recorded showing the simultaneous operation of the two combs, whose free-running coherence properties are investigated by means of beatnote spectroscopy performed both with an external detector and via self-mixing. Comb operation in a highly dispersive region (4.6 THz) relying only on gain bandwidth engineering shows the potential for broad spectral coverage with compact comb sources.
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30
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Klocke JL, Mangold M, Allmendinger P, Hugi A, Geiser M, Jouy P, Faist J, Kottke T. Single-Shot Sub-microsecond Mid-infrared Spectroscopy on Protein Reactions with Quantum Cascade Laser Frequency Combs. Anal Chem 2018; 90:10494-10500. [DOI: 10.1021/acs.analchem.8b02531] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Jessica L. Klocke
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany
| | - Markus Mangold
- IRsweep AG, Laubisruetistrasse 44, 8712 Staefa, Switzerland
| | | | - Andreas Hugi
- IRsweep AG, Laubisruetistrasse 44, 8712 Staefa, Switzerland
| | - Markus Geiser
- IRsweep AG, Laubisruetistrasse 44, 8712 Staefa, Switzerland
| | - Pierre Jouy
- Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland
| | - Jérôme Faist
- Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland
| | - Tilman Kottke
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany
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31
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Hillbrand J, Jouy P, Beck M, Faist J. Tunable dispersion compensation of quantum cascade laser frequency combs. Opt Lett 2018; 43:1746-1749. [PMID: 29652355 DOI: 10.1364/ol.43.001746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 03/06/2018] [Indexed: 06/08/2023]
Abstract
Compensating for group velocity dispersion is an important challenge to achieve stable midinfrared quantum cascade laser (QCL) frequency combs with large spectral coverage. We present a tunable dispersion compensation scheme consisting of a planar mirror placed behind the back facet of the QCL. Dispersion can be either enhanced or decreased depending on the position of the mirror. We demonstrate that the fraction of the comb regime in the dynamic range of the laser increases considerably when the dispersion induced by the Gires-Tournois interferometer compensates the intrinsic dispersion of the laser. Furthermore, it is possible to tune to the offset frequency of the comb with the Gires-Tournois interferometer while the repetition frequency is almost unaffected.
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32
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Palaferri D, Todorov Y, Bigioli A, Mottaghizadeh A, Gacemi D, Calabrese A, Vasanelli A, Li L, Davies AG, Linfield EH, Kapsalidis F, Beck M, Faist J, Sirtori C. Room-temperature nine-µm-wavelength photodetectors and GHz-frequency heterodyne receivers. Nature 2018; 556:85-88. [DOI: 10.1038/nature25790] [Citation(s) in RCA: 146] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 01/16/2018] [Indexed: 11/09/2022]
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33
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Keller J, Scalari G, Cibella S, Maissen C, Appugliese F, Giovine E, Leoni R, Beck M, Faist J. Few-Electron Ultrastrong Light-Matter Coupling at 300 GHz with Nanogap Hybrid LC Microcavities. Nano Lett 2017; 17:7410-7415. [PMID: 29172537 DOI: 10.1021/acs.nanolett.7b03228] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Ultrastrong light-matter coupling allows the exploration of new states of matter through the interaction of strong vacuum fields with huge electronic dipoles. By using hybrid dipole antenna-split ring resonator-based cavities with extremely small effective mode volumes Veff/λ03 ≃ 6 × 10-10 and surfaces Seff/λ02 ≃ 3.5 × 10-7, we probe the ultrastrong light-matter coupling at 300 GHz to less than 100 electrons located in the last occupied Landau level of a high mobility two-dimensional electron gas, measuring a normalized coupling ratio of ΩR/ωc = 0.36. Effects of the extremely reduced cavity dimensions are observed as the light-matter coupled system is better described by an effective mass heavier than the uncoupled one. These results open the way to ultrastrong coupling at the single-electron level in two-dimensional electron systems.
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Affiliation(s)
- Janine Keller
- ETH Zürich, Institute of Quantum Electronics , Auguste-Piccard-Hof 1, Zürich 8093, Switzerland
| | - Giacomo Scalari
- ETH Zürich, Institute of Quantum Electronics , Auguste-Piccard-Hof 1, Zürich 8093, Switzerland
| | - Sara Cibella
- Istituto di Fotonica e Nanotecnologie (IFN), CNR , via Cineto Romano 42, 00156 Rome, Italy
| | - Curdin Maissen
- ETH Zürich, Institute of Quantum Electronics , Auguste-Piccard-Hof 1, Zürich 8093, Switzerland
| | - Felice Appugliese
- ETH Zürich, Institute of Quantum Electronics , Auguste-Piccard-Hof 1, Zürich 8093, Switzerland
| | - Ennio Giovine
- Istituto di Fotonica e Nanotecnologie (IFN), CNR , via Cineto Romano 42, 00156 Rome, Italy
| | - Roberto Leoni
- Istituto di Fotonica e Nanotecnologie (IFN), CNR , via Cineto Romano 42, 00156 Rome, Italy
| | - Mattias Beck
- ETH Zürich, Institute of Quantum Electronics , Auguste-Piccard-Hof 1, Zürich 8093, Switzerland
| | - Jérôme Faist
- ETH Zürich, Institute of Quantum Electronics , Auguste-Piccard-Hof 1, Zürich 8093, Switzerland
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Wang Z, Liang Y, Yin X, Peng C, Hu W, Faist J. Analytical coupled-wave model for photonic crystal surface-emitting quantum cascade lasers. Opt Express 2017; 25:11997-12007. [PMID: 28788754 DOI: 10.1364/oe.25.011997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
An analytical coupled-wave model is developed for surface-emitting photonic-crystal quantum cascade lasers (PhC-QCLs). This model provides an accurate and efficient analysis of full three-dimensional device structure with large-area cavity size. Various laser properties of interest including the band structure, mode frequency, cavity loss, mode intensity profile, and far field pattern (FFP), as well as their dependence on PhC structures and cavity size, are investigated. Comparison with numerical simulations confirms the accuracy and validity of our model. The calculated FFP and polarization profile well explain the previously reported experimental results. In particular, we reveal the possibility of switching the lasing modes and generating single-lobed FFP by properly tuning PhC structures.
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Deutsch C, Kainz MA, Krall M, Brandstetter M, Bachmann D, Schönhuber S, Detz H, Zederbauer T, MacFarland D, Andrews AM, Schrenk W, Beck M, Ohtani K, Faist J, Strasser G, Unterrainer K. High-Power Growth-Robust InGaAs/InAlAs Terahertz Quantum Cascade Lasers. ACS Photonics 2017; 4:957-962. [PMID: 28470028 PMCID: PMC5407654 DOI: 10.1021/acsphotonics.7b00009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Indexed: 06/07/2023]
Abstract
We report on high-power terahertz quantum cascade lasers based on low effective electron mass InGaAs/InAlAs semiconductor heterostructures with excellent reproducibility. Growth-related asymmetries in the form of interface roughness and dopant migration play a crucial role in this material system. These bias polarity dependent phenomena are studied using a nominally symmetric active region resulting in a preferential electron transport in the growth direction. A structure based on a three-well optical phonon depletion scheme was optimized for this bias direction. Depending on the sheet doping density, the performance of this structure shows a trade-off between high maximum operating temperature and high output power. While the highest operating temperature of 155 K is observed for a moderate sheet doping density of 2 × 1010 cm-2, the highest peak output power of 151 mW is found for 7.3 × 1010 cm-2. Furthermore, by abutting a hyperhemispherical GaAs lens to a device with the highest doping level a record output power of 587 mW is achieved for double-metal waveguide structures.
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Affiliation(s)
- Christoph Deutsch
- Photonics
Institute, TU Wien, Gußhausstraße 27-29, 1040 Vienna, Austria
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
| | - Martin Alexander Kainz
- Photonics
Institute, TU Wien, Gußhausstraße 27-29, 1040 Vienna, Austria
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
| | - Michael Krall
- Photonics
Institute, TU Wien, Gußhausstraße 27-29, 1040 Vienna, Austria
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
| | - Martin Brandstetter
- Photonics
Institute, TU Wien, Gußhausstraße 27-29, 1040 Vienna, Austria
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
| | - Dominic Bachmann
- Photonics
Institute, TU Wien, Gußhausstraße 27-29, 1040 Vienna, Austria
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
| | - Sebastian Schönhuber
- Photonics
Institute, TU Wien, Gußhausstraße 27-29, 1040 Vienna, Austria
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
| | - Hermann Detz
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
- Austrian
Academy of Sciences, Dr. Ignaz Seipel-Platz 2, 1010 Vienna, Austria
| | - Tobias Zederbauer
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
| | - Donald MacFarland
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
| | - Aaron Maxwell Andrews
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
| | - Werner Schrenk
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
| | - Mattias Beck
- Institute
for Quantum Electronics, ETH Zurich, Auguste-Piccard-Hof 1, 8093 Zurich, Switzerland
| | - Keita Ohtani
- Institute
for Quantum Electronics, ETH Zurich, Auguste-Piccard-Hof 1, 8093 Zurich, Switzerland
| | - Jérôme Faist
- Institute
for Quantum Electronics, ETH Zurich, Auguste-Piccard-Hof 1, 8093 Zurich, Switzerland
| | - Gottfried Strasser
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
| | - Karl Unterrainer
- Photonics
Institute, TU Wien, Gußhausstraße 27-29, 1040 Vienna, Austria
- Institute of Solid State Electronics and Center for Micro-
and Nanostructures, TU Wien, Floragasse 7, 1040 Vienna, Austria
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Bidaux Y, Sergachev I, Wuester W, Maulini R, Gresch T, Bismuto A, Blaser S, Muller A, Faist J. Plasmon-enhanced waveguide for dispersion compensation in mid-infrared quantum cascade laser frequency combs. Opt Lett 2017; 42:1604-1607. [PMID: 28409809 DOI: 10.1364/ol.42.001604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We demonstrate dispersion compensation in mid-infrared quantum cascade laser frequency combs (FCs) emitting at 7.8 μm using the coupling of a dielectric waveguide to a plasmonic resonance in the top cladding layer of the latter. Devices with group velocity dispersion lower than 110 fs2/mm were fabricated, and narrow beatnotes with FWHM linewidths below 1 kHz were measured on the entire operation range. At -20°C, the optical output power reaches 275 mW, and the optical spectrum spans 60 cm-1. The multi-heterodyne beating spectrum of two devices was measured and spans 46 cm-1, demonstrating the potential of dispersion-engineered waveguides for the fabrication of highly stable and reliable quantum cascade laser FCs with high output power across the mid-infrared.
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Poumirol JM, Liu PQ, Slipchenko TM, Nikitin AY, Martin-Moreno L, Faist J, Kuzmenko AB. Electrically controlled terahertz magneto-optical phenomena in continuous and patterned graphene. Nat Commun 2017; 8:14626. [PMID: 28266509 PMCID: PMC5344301 DOI: 10.1038/ncomms14626] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/18/2017] [Indexed: 11/22/2022] Open
Abstract
The magnetic circular dichroism and the Faraday rotation are the fundamental phenomena of great practical importance arising from the breaking of the time reversal symmetry by a magnetic field. In most materials, the strength and the sign of these effects can be only controlled by the field value and its orientation. Furthermore, the terahertz range is lacking materials having the ability to affect the polarization state of the light in a non-reciprocal manner. Here we demonstrate, using broadband terahertz magneto-electro-optical spectroscopy, that in graphene both the magnetic circular dichroism and the Faraday rotation can be modulated in intensity, tuned in frequency and, importantly, inverted using only electrostatic doping at a fixed magnetic field. In addition, we observe strong magneto-plasmonic resonances in a patterned array of graphene antidots, which potentially allows exploiting these magneto-optical phenomena in a broad THz range. Time reversal symmetry breaking gives rise to magnetic circular dichroism and Faraday rotation in graphene. The authors use terahertz magneto-electro-optical spectroscopy to demonstrate that electrostatic doping at a fixed magnetic field allows inversion of magnetic circular dichroism and Faraday rotation.
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Affiliation(s)
- Jean-Marie Poumirol
- Department of Quantum Matter Physics, University of Geneva, Geneva 4 CH-1211, Switzerland
| | - Peter Q Liu
- Institute for Quantum Electronics, Department of Physics, ETH Zurich, Zurich CH-8093, Switzerland
| | - Tetiana M Slipchenko
- Instituto de Ciencia de Materiales de Aragon and Departamento de Fisica de la Materia Condensada, CSIC-Universidad de Zaragoza, Zaragoza E-50009, Spain
| | - Alexey Y Nikitin
- CIC nanoGUNE, Donostia-San Sebastián E-20018, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Spain
| | - Luis Martin-Moreno
- Instituto de Ciencia de Materiales de Aragon and Departamento de Fisica de la Materia Condensada, CSIC-Universidad de Zaragoza, Zaragoza E-50009, Spain
| | - Jérôme Faist
- Institute for Quantum Electronics, Department of Physics, ETH Zurich, Zurich CH-8093, Switzerland
| | - Alexey B Kuzmenko
- Department of Quantum Matter Physics, University of Geneva, Geneva 4 CH-1211, Switzerland
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38
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Bidaux Y, Bismuto A, Patimisco P, Sampaolo A, Gresch T, Strubi G, Blaser S, Tittel FK, Spagnolo V, Muller A, Faist J. Mid infrared quantum cascade laser operating in pure amplitude modulation for background-free trace gas spectroscopy. Opt Express 2016; 24:26464-26471. [PMID: 27857379 DOI: 10.1364/oe.24.026464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a single mode multi-section quantum cascade laser source composed of three different sections: master oscillator, gain and phase section. Non-uniform pumping of the QCL's gain reveals that the various laser sections are strongly coupled. Simulations of the electronic and optical properties of the laser (based on the density matrix and scattering matrix formalisms, respectively) were performed and a good agreement with measurements is obtained. In particular, a pure modulation of the laser output power can be achieved. This capability of the device is applied in tunable-laser spectroscopy of N2O where background-free quartz enhanced photo acoustic spectral scans with nearly perfect Voigt line shapes for the selected absorption line are obtained.
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Tardif S, Gassenq A, Guilloy K, Pauc N, Osvaldo Dias G, Hartmann JM, Widiez J, Zabel T, Marin E, Sigg H, Faist J, Chelnokov A, Reboud V, Calvo V, Micha JS, Robach O, Rieutord F. Lattice strain and tilt mapping in stressed Ge microstructures using X-ray Laue micro-diffraction and rainbow filtering. J Appl Crystallogr 2016. [DOI: 10.1107/s1600576716010347] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Laue micro-diffraction and simultaneous rainbow-filtered micro-diffraction were used to measure accurately the full strain tensor and the lattice orientation distribution at the sub-micrometre scale in highly strained, suspended Ge micro-devices. A numerical approach to obtain the full strain tensor from the deviatoric strain measurement alone is also demonstrated and used for faster full strain mapping. The measurements were performed in a series of micro-devices under either uniaxial or biaxial stress and an excellent agreement with numerical simulations was found. This shows the superior potential of Laue micro-diffraction for the investigation of highly strained micro-devices.
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Hinkov B, Hugi A, Beck M, Faist J. Rf-modulation of mid-infrared distributed feedback quantum cascade lasers. Opt Express 2016; 24:3294-3312. [PMID: 26906992 DOI: 10.1364/oe.24.003294] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present the electrical and optical characterization and theoretical modeling of the transient behavior of regular 4.5-μm single-mode emitting distributed feedback (DFB) quantum cascade lasers (QCLs). Low residual capacitance together with a high-frequency optimized three-terminal coplanar waveguide configuration leads to modulation frequencies up to 23.5 GHz (optical) and 26.5 GHz (electrical), respectively. A maximum 3-dB cut-off value of 6.6 GHz in a microwave rectification scheme is obtained, with a significant increase in electrical modulation bandwidth when increasing the DC-current for the entire current range of the devices. Optical measurements by means of FTIR-spectroscopy and a heterodyne beating experiment reveal the presence of a resonance peak, due to coupling of the lasing DFB- with its neighboring below-threshold Fabry-Pérot-(FP-)mode, when modulating around the cavity roundtrip frequency. This resonance is modeled by a 2-mode Maxwell-Bloch formalism. It enhances only one sideband and consequently leads to the first experimental observation of the single-sideband regime in such kind of devices.
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41
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Wolf JM, Riedi S, Süess MJ, Beck M, Faist J. 3.36 µm single-mode quantum cascade laser with a dissipation below 250 mW. Opt Express 2016; 24:662-671. [PMID: 26832296 DOI: 10.1364/oe.24.000662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present 3.36 µm buried heterostructure distributed-feedback quantum cascade lasers with a power dissipation at threshold below 250 mW and operation temperatures as high as 130 °C. Threshold values below 20 mA at -10 °C in pulsed operation and 30 mA at -20 °C in continuous-wave operation are reported. Optical power above 130 mW and 13 mW are achieved at -20 °C in pulsed and continuous-wave operation, respectively. Continuous-wave operation occurs until 15 °C. We show single-mode emission in pulsed and continuous-wave operation. Single-mode performance is demonstrated in long pulse (5.56 µs) operation. The laser far-field exhibits a single lobe emission with full-width-half-max of 27 ° × 34 °.
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Emmenegger L, Jágerská J, Brönnimann R, Faist J, Jouy P, Looser H, Soltic P, Tuzson B. Multi-Component Trace Gas Spectroscopy Using Dual-Wavelength Quantum Cascade Lasers. Chimia (Aarau) 2015; 69:708. [PMID: 26671057 DOI: 10.2533/chimia.2015.708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Lukas Emmenegger
- Empa, Swiss Federal Laboratories for Materials Testing and Research, CH-8600 Dübendorf, Switzerland.
| | - Jana Jágerská
- Department of Physics and Technology, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Rolf Brönnimann
- Empa, Swiss Federal Laboratories for Materials Testing and Research, CH-8600 Dübendorf, Switzerland
| | - Jérôme Faist
- Institute for Quantum Electronics, ETH, CH-8093 Zürich, Switzerland
| | - Pierre Jouy
- Institute for Aerosol and Sensor Technology, FHNW, CH-5210 Windisch, Switzerland
| | - Herbert Looser
- Institute for Aerosol and Sensor Technology, FHNW, CH-5210 Windisch, Switzerland
| | - Patrik Soltic
- Empa, Swiss Federal Laboratories for Materials Testing and Research, CH-8600 Dübendorf, Switzerland
| | - Béla Tuzson
- Empa, Swiss Federal Laboratories for Materials Testing and Research, CH-8600 Dübendorf, Switzerland
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Riedi S, Cappelli F, Blaser S, Baroni PY, Müller A, Faist J. Broadband superluminescence, 5.9 μm to 7.2 μm, of a quantum cascade gain device. Opt Express 2015; 23:7184-7189. [PMID: 25837063 DOI: 10.1364/oe.23.007184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The broadband electroluminescence of a quantum cascade device based on a multi-color active region covering the wavelengths 5.9 μm - 7.2 μm was measured. Anti-reflection coatings were applied on both cleaved facets to remove the Fabry-Pérot cavity and prevent the device from lasing. This allows the latter to be studied either as a superluminescent diode or a single-pass amplifier in order to determine its suitability as a source for low speckle imaging applications. At 243 K, the amplified spontaneous emission has a peak power of 38 μW that agrees well with a simple model of spontaneous emission intensity. The light of a similar structure could be modulated up to 1 GHz, limited by the RC constant of the device. The peak gain was measured from high-resolution luminescence spectra and determined to be 6.3 cm⁻¹, corresponding to a single-pass gain of 1.89.
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Franckié M, Winge DO, Wolf J, Liverini V, Dupont E, Trinité V, Faist J, Wacker A. Impact of interface roughness distributions on the operation of quantum cascade lasers. Opt Express 2015; 23:5201-5212. [PMID: 25836553 DOI: 10.1364/oe.23.005201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We study the impact of interface roughness on the operation of mid-IR and THz quantum cascade lasers. Particular emphasis is given towards the differences between the Gaussian and exponential roughness distribution functions, for which we present results from simulation packages based on nonequilibrium Green's functions and density matrices. The Gaussian distribution suppresses scattering at high momentum transfer which enhances the lifetime of the upper laser level in mid-IR lasers. For THz lasers, a broader range of scattering transitions is of relevance, which is sensitive to the entire profile of the interface fluctuations. Furthermore we discuss the implementation of interface roughness within a two band model.
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Bachmann D, Leder N, Rösch M, Scalari G, Beck M, Arthaber H, Faist J, Unterrainer K, Darmo J. Broadband terahertz amplification in a heterogeneous quantum cascade laser. Opt Express 2015; 23:3117-3125. [PMID: 25836170 DOI: 10.1364/oe.23.003117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We demonstrate a broadband terahertz amplifier based on ultrafast gain switching in a quantum cascade laser. A heterogeneous active region is processed into a coupled cavity metal-metal waveguide device and provides broadband terahertz gain that allows achieving an amplification bandwidth of more than 500 GHz. The temporal and spectral evolution of a terahertz seed pulse, which is generated in an integrated emitter section, is presented and an amplification factor of 21 dB is reached. Furthermore, the quantum cascade amplifier emission spectrum of the emerging sub-nanosecond terahertz pulse train is measured by time-domain spectroscopy and reveals discrete modes between 2.14 and 2.68 THz.
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Jágerská J, Jouy P, Tuzson B, Looser H, Mangold M, Soltic P, Hugi A, Brönnimann R, Faist J, Emmenegger L. Simultaneous measurement of NO and NO(2) by dual-wavelength quantum cascade laser spectroscopy. Opt Express 2015; 23:1512-1522. [PMID: 25835908 DOI: 10.1364/oe.23.001512] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The concept of a multi-wavelength quantum cascade laser emitting at two or more spectrally well-separated wavelengths is highly appealing for applied spectroscopy, as it allows detecting several species with compact and cost-efficient optical setups. Here we present a practical realization of such a dual-wavelength setup, which is based on a room-temperature quantum cascade laser emitting single-mode at 1600 cm-1 and 1900 cm-1 and is thus well-suited for simultaneous NO and NO2 detection. Operated in a time-division multiplexed mode, our spectrometer reaches detection limits of 0.5 and 1.5 ppb for NO2 and NO, respectively. The performance of the system is validated against the well-established chemiluminescence detection while measuring the NOx emissions on an automotive test-bench, as well as upon monitoring the pollution at a suburban site.
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Abstract
Frequency comb formation in quantum cascade lasers is studied theoretically using a Maxwell-Bloch formalism based on a modal decomposition, where dispersion is considered. In the mid-infrared, comb formation persists in the presence of weak cavity dispersion (500 fs2 mm-1) but disappears when much larger values are used (30'000 fs2 mm-1). Active modulation at the round-trip frequency is found to induce mode-locking in THz devices, where the upper state lifetime is in the tens of picoseconds. Our results show that mode-locking based on four-wave mixing in broadband gain, low dispersion cavities is the most promising way of achieving broadband quantum cascade laser frequency combs.
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48
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Villares G, Hugi A, Blaser S, Faist J. Dual-comb spectroscopy based on quantum-cascade-laser frequency combs. Nat Commun 2014; 5:5192. [PMID: 25307936 DOI: 10.1038/ncomms6192] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 09/09/2014] [Indexed: 11/09/2022] Open
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Abstract
In this work, we present GaInAs/AlAs/AlInAs quantum cascade lasers emitting from 3.2 to 3.4 μm. Single-mode emission is obtained using buried distributed-feedback gratings fabricated using standard deep-UV contact lithography. This technique can easily be transferred to industrial production. Devices with single-mode emission down to 3.19 μm were achieved with peak power of up to 250 mW at -20 °C. A tuning range of 11 cm(-1) was obtained by changing the device temperature between -30 °C and 20 °C.
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Abstract
Intersubband polaritons in the THz range are observed by coupling intersubband transitions in parabolic quantum wells to metallic microcavities. The polaritonic states are tuned in frequency by electrically modulating the electron density in the device using a gate. Tuning of 140 Ghz is observed at a lower polariton frequency of 2.5 THz in reflection measurements. Biasing the structure for electroluminescence measurements also modulates the electron density, which can lead to differential electroluminescence line shapes.
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