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Hong QQ, Lian ZZ, Shu CC, Henriksen NE. Quantum control of field-free molecular orientation. Phys Chem Chem Phys 2023. [PMID: 37724061 DOI: 10.1039/d3cp03115b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
Generating field-free (non-stationary) orientation of molecules in space has been a longstanding goal in the field of quantum control of molecular rotation, which has significant applications in physical chemistry, chemical physics, strong-field physics, and quantum information science. In this Perspective, we review and examine several representative control schemes developed in recent years and implemented in theoretical and experimental areas for generating field-free orientation of molecules. By conducting numerical simulations of different control schemes on the same molecular system, we demonstrate that quantum coherent control, specifically targeting a limited number of the lowest-lying rotational levels to achieve an optimal superposition, can result in a high degree of orientation. To this end, we provide an overview of our latest developed analytical method, which enables the precise design of terahertz field parameters through resonant excitation. This design approach facilitates the attainment of desired field-free orientations by optimizing the amplitudes and phases of rotational wave functions for the selected rotational levels. Finally, we outlook the significance of such progress in multiple frontier research fields, highlighting its potential applications in ultracold physics, quantum computation, quantum simulation, and quantum metrology.
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Affiliation(s)
- Qian-Qian Hong
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics and Electronics, Central South University, Changsha 410083, China.
| | - Zhen-Zhong Lian
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics and Electronics, Central South University, Changsha 410083, China.
| | - Chuan-Cun Shu
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics and Electronics, Central South University, Changsha 410083, China.
| | - Niels E Henriksen
- Department of Chemistry, Technical University of Denmark, Building 207, DK-2800 Kongens Lyngby, Denmark
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2
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Wu X, Kong D, Hao S, Zeng Y, Yu X, Zhang B, Dai M, Liu S, Wang J, Ren Z, Chen S, Sang J, Wang K, Zhang D, Liu Z, Gui J, Yang X, Xu Y, Leng Y, Li Y, Song L, Tian Y, Li R. Generation of 13.9-mJ Terahertz Radiation from Lithium Niobate Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208947. [PMID: 36932897 DOI: 10.1002/adma.202208947] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 03/12/2023] [Indexed: 06/09/2023]
Abstract
Extremely strong-field terahertz (THz) radiation in free space has compelling applications in nonequilibrium condensed matter state regulation, all-optical THz electron acceleration and manipulation, THz biological effects, etc. However, these practical applications are constrained by the absence of high-intensity, high-efficiency, high-beam-quality, and stable solid-state THz light sources. Here, the generation of single-cycle 13.9-mJ extreme THz pulses from cryogenically cooled lithium niobate crystals and a 1.2% energy conversion efficiency from 800 nm to THz are demonstrated experimentally using the tilted pulse-front technique driven by a home-built 30-fs, 1.2-Joule Ti:sapphire laser amplifier. The focused peak electric field strength is estimated to be 7.5 MV cm-1 . A record of 1.1-mJ THz single-pulse energy at a 450 mJ pump at room temperature is produced and observed that the self-phase modulation of the optical pump can induce THz saturation behavior from the crystals in the substantially nonlinear pump regime. This study lays the foundation for the generation of sub-Joule THz radiation from lithium niobate crystals and will inspire more innovations in extreme THz science and applications.
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Affiliation(s)
- Xiaojun Wu
- School of Electronic and Information Engineering, and School of Cyber Science and Technology, Beihang University, Beijing, 100191, China
- Zhangjiang Laboratory, 100 Haike Road, Shanghai, 201210, China
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Deyin Kong
- School of Electronic and Information Engineering, and School of Cyber Science and Technology, Beihang University, Beijing, 100191, China
- Zhangjiang Laboratory, 100 Haike Road, Shanghai, 201210, China
| | - Sibo Hao
- School of Electronic and Information Engineering, and School of Cyber Science and Technology, Beihang University, Beijing, 100191, China
| | - Yushan Zeng
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Xieqiu Yu
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Baolong Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Mingcong Dai
- School of Electronic and Information Engineering, and School of Cyber Science and Technology, Beihang University, Beijing, 100191, China
| | - Shaojie Liu
- School of Electronic and Information Engineering, and School of Cyber Science and Technology, Beihang University, Beijing, 100191, China
| | - Jiaqi Wang
- School of Electronic and Information Engineering, and School of Cyber Science and Technology, Beihang University, Beijing, 100191, China
| | - Zejun Ren
- School of Electronic and Information Engineering, and School of Cyber Science and Technology, Beihang University, Beijing, 100191, China
| | - Sai Chen
- School of Electronic and Information Engineering, and School of Cyber Science and Technology, Beihang University, Beijing, 100191, China
| | - Jianhua Sang
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Kang Wang
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Dongdong Zhang
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Zhongkai Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai, 201210, China
| | - Jiayan Gui
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Xiaojun Yang
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Yi Xu
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Yuxin Leng
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Yutong Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Liwei Song
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Ye Tian
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Ruxin Li
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China
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3
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Kumar M, Song HS, Lee J, Park D, Suk H, Hur MS. Intense multicycle THz pulse generation from laser-produced nanoplasmas. Sci Rep 2023; 13:4233. [PMID: 36918732 PMCID: PMC10015041 DOI: 10.1038/s41598-023-31427-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 03/11/2023] [Indexed: 03/16/2023] Open
Abstract
We present a novel scheme to obtain robust, narrowband, and tunable THz emission using a nano-dimensional overdense plasma target, irradiated by two counter-propagating detuned laser pulses. So far, no narrowband THz sources with a field strength of GV/m-level have been reported from laser-solid interaction (mostly half-or single-cycle THz pulses with only broadband frequency spectrum). From two- and three-dimensional particle-in-cell simulations, we find that the strong plasma current generated by the beat ponderomotive force in the colliding region, produces beat-frequency radiation in the THz range. Here we report intense THz pulses [Formula: see text]THz) with an unprecedentedly high peak field strength of 11.9 GV/m and spectral width [Formula: see text], which leads to a regime of an extremely bright narrowband THz source of TW/cm[Formula: see text], suitable for various ambitious applications.
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Affiliation(s)
- Manoj Kumar
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, 44919, Republic of Korea
| | - Hyung Seon Song
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, 44919, Republic of Korea
| | - Jaeho Lee
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, 44919, Republic of Korea
| | - Dohyun Park
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, 44919, Republic of Korea
| | - Hyyong Suk
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea
| | - Min Sup Hur
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, 44919, Republic of Korea.
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4
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Wavelength conversion through plasmon-coupled surface states. Nat Commun 2021; 12:4641. [PMID: 34330930 PMCID: PMC8324784 DOI: 10.1038/s41467-021-24957-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/12/2021] [Indexed: 11/17/2022] Open
Abstract
Surface states generally degrade semiconductor device performance by raising the charge injection barrier height, introducing localized trap states, inducing surface leakage current, and altering the electric potential. We show that the giant built-in electric field created by the surface states can be harnessed to enable passive wavelength conversion without utilizing any nonlinear optical phenomena. Photo-excited surface plasmons are coupled to the surface states to generate an electron gas, which is routed to a nanoantenna array through the giant electric field created by the surface states. The induced current on the nanoantennas, which contains mixing product of different optical frequency components, generates radiation at the beat frequencies of the incident photons. We utilize the functionalities of plasmon-coupled surface states to demonstrate passive wavelength conversion of nanojoule optical pulses at a 1550 nm center wavelength to terahertz regime with efficiencies that exceed nonlinear optical methods by 4-orders of magnitude. Semiconductor surface states often stand in the way of device performance, but here, the authors take advantage of them for wavelength conversion. They present a compact, passive conversion device insensitive to optical alignment by using plasmon-coupled surface states that enable the efficient conversion without nonlinear phenomena.
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5
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Déchard J, Debayle A, Davoine X, Gremillet L, Bergé L. Terahertz Pulse Generation in Underdense Relativistic Plasmas: From Photoionization-Induced Radiation to Coherent Transition Radiation. PHYSICAL REVIEW LETTERS 2018; 120:144801. [PMID: 29694108 DOI: 10.1103/physrevlett.120.144801] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 01/25/2018] [Indexed: 06/08/2023]
Abstract
Terahertz to far-infrared emission by two-color, ultrashort optical pulses interacting with underdense helium gases at ultrahigh intensities (>10^{19} W/cm^{2}) is investigated by means of 3D particle-in-cell simulations. The terahertz field is shown to be produced by two mechanisms occurring sequentially, namely, photoionization-induced radiation (PIR) by the two-color pulse, and coherent transition radiation (CTR) by the wakefield-accelerated electrons escaping the plasma. We exhibit laser-plasma parameters for which CTR proves to be the dominant process, providing terahertz bursts with field strength as high as 100 GV/m and energy in excess of 10 mJ. Analytical models are developed for both the PIR and CTR processes, which correctly reproduce the simulation data.
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Affiliation(s)
- J Déchard
- CEA, DAM, DIF, F-91297 Arpajon, France
| | - A Debayle
- CEA, DAM, DIF, F-91297 Arpajon, France
| | - X Davoine
- CEA, DAM, DIF, F-91297 Arpajon, France
| | | | - L Bergé
- CEA, DAM, DIF, F-91297 Arpajon, France
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6
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Teuscher J, Brauer JC, Stepanov A, Solano A, Boziki A, Chergui M, Wolf JP, Rothlisberger U, Banerji N, Moser JE. Charge separation and carrier dynamics in donor-acceptor heterojunction photovoltaic systems. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:061503. [PMID: 29308415 PMCID: PMC5736396 DOI: 10.1063/1.4996409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 11/13/2017] [Indexed: 05/16/2023]
Abstract
Electron transfer and subsequent charge separation across donor-acceptor heterojunctions remain the most important areas of study in the field of third-generation photovoltaics. In this context, it is particularly important to unravel the dynamics of individual ultrafast processes (such as photoinduced electron transfer, carrier trapping and association, and energy transfer and relaxation), which prevail in materials and at their interfaces. In the frame of the National Center of Competence in Research "Molecular Ultrafast Science and Technology," a research instrument of the Swiss National Science Foundation, several groups active in the field of ultrafast science in Switzerland have applied a number of complementary experimental techniques and computational simulation tools to scrutinize these critical photophysical phenomena. Structural, electronic, and transport properties of the materials and the detailed mechanisms of photoinduced charge separation in dye-sensitized solar cells, conjugated polymer- and small molecule-based organic photovoltaics, and high-efficiency lead halide perovskite solar energy converters have been scrutinized. Results yielded more than thirty research articles, an overview of which is provided here.
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Affiliation(s)
| | - Jan C Brauer
- FemtoMat Group, Department of Chemistry, Université de Fribourg, 1700 Fribourg, Switzerland
| | - Andrey Stepanov
- GAP-Biophotonics Group, Department of Applied Physics, Université de Genève, 1205 Geneva, Switzerland
| | | | | | | | - Jean-Pierre Wolf
- GAP-Biophotonics Group, Department of Applied Physics, Université de Genève, 1205 Geneva, Switzerland
| | | | - Natalie Banerji
- FemtoMat Group, Department of Chemistry, Université de Fribourg, 1700 Fribourg, Switzerland
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7
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Bodrov S, Sergeev Y, Murzanev A, Stepanov A. Terahertz induced optical birefringence in polar and nonpolar liquids. J Chem Phys 2017; 147:084507. [PMID: 28863517 DOI: 10.1063/1.5000374] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The terahertz induced optical birefringence in liquids with polar (acetone, chloroform) and nonpolar (benzene, carbon tetrachloride) molecules has been investigated. Fast and slow responses were extracted from the experimental data and compared with previous studies of the femtosecond optical Kerr effect. Terahertz Kerr constants were found and compared with known DC and optical constants. Analysis of the results obtained showed that, in contrast to the optical excitation, the interaction of a permanent dipole moment of molecules with a THz field makes a significant contribution to the transient birefringence and Kerr constants. This conclusion fully agrees with the direct comparison of the femtosecond optical and THz Kerr effects reported by Sajadi et al. [Nat. Commun. 8, 14963 (2017)].
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Affiliation(s)
- Sergey Bodrov
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950, Russia
| | - Yury Sergeev
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950, Russia
| | - Aleksey Murzanev
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950, Russia
| | - Andrey Stepanov
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950, Russia
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8
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Simulating electric field interactions with polar molecules using spectroscopic databases. Sci Rep 2017; 7:45068. [PMID: 28338042 PMCID: PMC5364483 DOI: 10.1038/srep45068] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 02/16/2017] [Indexed: 11/10/2022] Open
Abstract
Ro-vibrational Stark-associated phenomena of small polyatomic molecules are modelled using extensive spectroscopic data generated as part of the ExoMol project. The external field Hamiltonian is built from the computed ro-vibrational line list of the molecule in question. The Hamiltonian we propose is general and suitable for any polar molecule in the presence of an electric field. By exploiting precomputed data, the often prohibitively expensive computations associated with high accuracy simulations of molecule-field interactions are avoided. Applications to strong terahertz field-induced ro-vibrational dynamics of PH3 and NH3, and spontaneous emission data for optoelectrical Sisyphus cooling of H2CO and CH3Cl are discussed.
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9
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Gorgisyan I, Ischebeck R, Erny C, Dax A, Patthey L, Pradervand C, Sala L, Milne C, Lemke HT, Hauri CP, Katayama T, Owada S, Yabashi M, Togashi T, Abela R, Rivkin L, Juranić P. THz streak camera method for synchronous arrival time measurement of two-color hard X-ray FEL pulses. OPTICS EXPRESS 2017. [PMID: 29519055 DOI: 10.1364/oe.25.002080] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The two-color operation of free electron laser (FEL) facilities allows the delivery of two FEL pulses with different energies, which opens new possibilities for user experiments. Measuring the arrival time of both FEL pulses relative to the external experimental laser and to each other improves the temporal resolution of the experiments using the two-color FEL beam and helps to monitor the performance of the machine itself. This work reports on the first simultaneous measurement of the arrival times of two hard X-ray FEL pulses with the THz streak camera. Measuring the arrival time of the two FEL pulses, the relative delay between them was calculated and compared to the set values. Furthermore, we present the first comparison of the THz streak camera method to the method of FEL induced transient transmission. The results indicate a good agreement between the two methods.
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10
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Thiele I, Nuter R, Bousquet B, Tikhonchuk V, Skupin S, Davoine X, Gremillet L, Bergé L. Theory of terahertz emission from femtosecond-laser-induced microplasmas. Phys Rev E 2017; 94:063202. [PMID: 28085420 DOI: 10.1103/physreve.94.063202] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Indexed: 11/07/2022]
Abstract
We present a theoretical investigation of terahertz (THz) generation in laser-induced gas plasmas. The work is strongly motivated by recent experimental results on microplasmas, but our general findings are not limited to such a configuration. The electrons and ions are created by tunnel ionization of neutral atoms, and the resulting plasma is heated by collisions. Electrons are driven by electromagnetic, convective, and diffusive sources and produce a macroscopic current which is responsible for THz emission. The model naturally includes both ionization current and transition-Cherenkov mechanisms for THz emission, which are usually investigated separately in the literature. The latter mechanism is shown to dominate for single-color multicycle laser pulses, where the observed THz radiation originates from longitudinal electron currents. However, we find that the often discussed oscillations at the plasma frequency do not contribute to the THz emission spectrum. In order to predict the scaling of the conversion efficiency with pulse energy and focusing conditions, we propose a simplified description that is in excellent agreement with rigorous particle-in-cell simulations.
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Affiliation(s)
- I Thiele
- Univ. Bordeaux-CNRS-CEA, Centre Lasers Intenses et Applications, UMR 5107, 33405 Talence, France
| | - R Nuter
- Univ. Bordeaux-CNRS-CEA, Centre Lasers Intenses et Applications, UMR 5107, 33405 Talence, France
| | - B Bousquet
- Univ. Bordeaux-CNRS-CEA, Centre Lasers Intenses et Applications, UMR 5107, 33405 Talence, France
| | - V Tikhonchuk
- Univ. Bordeaux-CNRS-CEA, Centre Lasers Intenses et Applications, UMR 5107, 33405 Talence, France
| | - S Skupin
- Univ. Bordeaux-CNRS-CEA, Centre Lasers Intenses et Applications, UMR 5107, 33405 Talence, France
| | - X Davoine
- CEA, DAM, DIF, 91297 Arpajon, France
| | | | - L Bergé
- CEA, DAM, DIF, 91297 Arpajon, France
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11
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Increased impedance near cut-off in plasma-like media leading to emission of high-power, narrow-bandwidth radiation. Sci Rep 2017; 7:40034. [PMID: 28071681 PMCID: PMC5223163 DOI: 10.1038/srep40034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 11/11/2016] [Indexed: 11/08/2022] Open
Abstract
Ultra-intense, narrow-bandwidth, electromagnetic pulses have become important tools for exploring the characteristics of matter. Modern tuneable high-power light sources, such as free-electron lasers and vacuum tubes, rely on bunching of relativistic or near-relativistic electrons in vacuum. Here we present a fundamentally different method for producing narrow-bandwidth radiation from a broad spectral bandwidth current source, which takes advantage of the inflated radiation impedance close to cut-off in a medium with a plasma-like permittivity. We find that by embedding a current source in this cut-off region, more than an order of magnitude enhancement of the radiation intensity is obtained compared with emission directly into free space. The method suggests a simple and general way to flexibly use broadband current sources to produce broad or narrow bandwidth pulses. As an example, we demonstrate, using particle-in-cell simulations, enhanced monochromatic emission of terahertz radiation using a two-colour pumped current source enclosed by a tapered waveguide.
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12
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Low frequency piezoresonance defined dynamic control of terahertz wave propagation. Sci Rep 2016; 6:38041. [PMID: 27901070 PMCID: PMC5128798 DOI: 10.1038/srep38041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 11/04/2016] [Indexed: 12/02/2022] Open
Abstract
Phase modulators are one of the key components of many applications in electromagnetic and opto-electric wave propagations. Phase-shifters play an integral role in communications, imaging and in coherent material excitations. In order to realize the terahertz (THz) electromagnetic spectrum as a fully-functional bandwidth, the development of a family of efficient THz phase modulators is needed. Although there have been quite a few attempts to implement THz phase modulators based on quantum-well structures, liquid crystals, or meta-materials, significantly improved sensitivity and dynamic control for phase modulation, as we believe can be enabled by piezoelectric-resonance devices, is yet to be investigated. In this article we provide an experimental demonstration of phase modulation of THz beam by operating a ferroelectric single crystal LiNbO3 film device at the piezo-resonance. The piezo-resonance, excited by an external a.c. electric field, develops a coupling between electromagnetic and lattice-wave and this coupling governs the wave propagation of the incident THz beam by modulating its phase transfer function. We report the understanding developed in this work can facilitate the design and fabrication of a family of resonance-defined highly sensitive and extremely low energy sub-millimeter wave sensors and modulators.
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13
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Erny C, Hauri CP. The SwissFEL Experimental Laser facility. JOURNAL OF SYNCHROTRON RADIATION 2016; 23:1143-50. [PMID: 27577769 DOI: 10.1107/s1600577516012595] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/04/2016] [Indexed: 05/19/2023]
Abstract
The hard X-ray laser SwissFEL at the Paul Scherrer Institute is currently being commissioned and will soon become available for users. In the current article the laser facility is presented, an integral part of the user facility, as most time-resolved experiments will require a versatile optical laser infrastructure and precise information about the relative delay between the X-ray and optical pulse. The important key parameters are a high availability and long-term stability while providing advanced laser performance in the wavelength range from ultraviolet to terahertz. The concept of integrating a Ti:sapphire laser amplifier system with subsequent frequency conversion stages and drift compensation into the SwissFEL facility environment for successful 24 h/7 d user operation is described.
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Affiliation(s)
- Christian Erny
- SwissFEL, Paul Scherrer Institute, Villigen PSI 5232, Switzerland
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14
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Zhong SC, Li J, Zhai ZH, Zhu LG, Li J, Zhou PW, Zhao JH, Li ZR. Generation of 0.19-mJ THz pulses in LiNbO 3 driven by 800-nm femtosecond laser. OPTICS EXPRESS 2016; 24:14828-14835. [PMID: 27410634 DOI: 10.1364/oe.24.014828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A cylindrical lens telescope tilted-pulse-front pumping scheme was proposed for high energy terahertz (THz) pulse generation. This scheme allows higher pump energy to be used with lower saturation effects under high pump fluence, and higher THz generation efficiency was achieved within large range of pump energy. The optimum pump pulse duration and crystal cooling temperature for THz generation in LiNbO3 (LN) crystal were also researched systematically. Excited by 800-nm laser, up to 0.19 mJ THz pulse energy and 0.27% conversion efficiency was demonstrated under 800-nm 400-fs laser excitation with ~100-mJ pulse energy and 150-K LN cooling temperature.
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15
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Terahertz radiation driven by two-color laser pulses at near-relativistic intensities: Competition between photoionization and wakefield effects. Sci Rep 2016; 6:26743. [PMID: 27255689 PMCID: PMC4891721 DOI: 10.1038/srep26743] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/05/2016] [Indexed: 11/26/2022] Open
Abstract
We numerically investigate terahertz (THz) pulse generation by linearly-polarized, two-color femtosecond laser pulses in highly-ionized argon. Major processes consist of tunneling photoionization and ponderomotive forces associated with transverse and longitudinal field excitations. By means of two-dimensional particle-in-cell (PIC) simulations, we reveal the importance of photocurrent mechanisms besides transverse and longitudinal plasma waves for laser intensities >1015 W/cm2. We demonstrate the following. (i) With two-color pulses, photoionization prevails in the generation of GV/m THz fields up to 1017 W/cm2 laser intensities and suddenly loses efficiency near the relativistic threshold, as the outermost electron shell of ionized Ar atoms has been fully depleted. (ii) PIC results can be explained by a one-dimensional Maxwell-fluid model and its semi-analytical solutions, offering the first unified description of the main THz sources created in plasmas. (iii) The THz power emitted outside the plasma channel mostly originates from the transverse currents.
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16
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Tu CM, Chou LH, Chen YC, Huang P, Rajaboopathi M, Luo CW, Wu KH, Krishnakumar V, Kobayashi T. THz emission from organic cocrystalline salt: 2, 6-diaminopyridinium-4-nitrophenolate-4-nitrophenol. OPTICS EXPRESS 2016; 24:5039-5044. [PMID: 29092332 DOI: 10.1364/oe.24.005039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We report few-cycle THz pulses emission from a novel organic crystal 2,6-diaminopyridinium-4-nitrophenolate-4-nitrophenol (DAP+NP-NP). The observed amplitude of the THz electric field from a DAP+NP-NP crystal is comparable with that from a ZnTe single crystal under the same optical pumping conditions. Both the waveform and spectra of the THz radiation from DAP+NP-NP are similar to those from ZnTe. We conclude that a high quality DAP+NP-NP crystal would be a high potential candidate in THz generation and applications.
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Ofori-Okai BK, Sivarajah P, Ronny Huang W, Nelson KA. THz generation using a reflective stair-step echelon. OPTICS EXPRESS 2016; 24:5057-5068. [PMID: 29092334 DOI: 10.1364/oe.24.005057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present a novel method for THz generation in lithium niobate using a reflective stair-step echelon structure. The echelon produces a discretely tilted pulse front with less angular dispersion compared to a high groove-density grating. The THz output was characterized using both a 1-lens and 3-lens imaging system to set the tilt angle at room and cryogenic temperatures. Using broadband 800 nm pulses with a pulse energy of 0.95 mJ and a pulse duration of 70 fs (24 nm FWHM bandwidth, 39 fs transform limited width), we produced THz pulses with field strengths as high as 500 kV/cm and pulse energies as high as 3.1 μJ. The highest conversion efficiency we obtained was 0.33%. In addition, we find that the echelon is easily implemented into an experimental setup for quick alignment and optimization.
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18
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Zhang QL, Yang RY, Jiang WZ, Huang ZQ. Fast water channeling across carbon nanotubes in far infrared terahertz electric fields. NANOSCALE 2016; 8:1886-1891. [PMID: 26739628 DOI: 10.1039/c5nr07281f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Using molecular dynamics simulations, we investigate systematically the water permeation properties across single-walled carbon nanotubes (SWCNT) in the presence of the terahertz electric field (TEF). With the TEF normal to the nanotube, the fracture of the hydrogen bonds results in the giant peak of net fluxes across the SWCNT with a three-fold enhancement centered around 14 THz. The phenomenon is attributed to the resonant mechanisms, characterized by librational, rotational, and rotation-induced responses of in-tube polar water molecules to the TEF. For the TEF along the symmetry axis of the nanotube, the vortical modes for resonances and consequently the enhancement of net fluxes are greatly suppressed by the alignment of polar water along the symmetry axis, which characterizes the quasi one-dimensional feature of the SWCNT nicely. The resonances of water molecules in the TEF can have potential applications in the high-flux device designs used for various purposes.
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Affiliation(s)
- Qi-Lin Zhang
- Department of Physics, Southeast University, Nanjing 211189, China. and Department of Mathematics and Physics, Anhui Polytechnic University, Anhui 241000, China
| | - Rong-Yao Yang
- Department of Physics, Southeast University, Nanjing 211189, China.
| | - Wei-Zhou Jiang
- Department of Physics, Southeast University, Nanjing 211189, China.
| | - Zi-Qian Huang
- Department of Physics, Southeast University, Nanjing 211189, China.
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Zhong SC, Zhai ZH, Li J, Zhu LG, Li J, Meng K, Liu Q, Du LH, Zhao JH, Li ZR. Optimization of terahertz generation from LiNbO 3 under intense laser excitation with the effect of three-photon absorption. OPTICS EXPRESS 2015; 23:31313-31323. [PMID: 26698758 DOI: 10.1364/oe.23.031313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We proposed a three-dimensional model to simulate terahertz generation from LiNbO3 crystal under intense laser excition (up to ~50 mJ/cm2). The impact of three-photon absorption, which leads to free carrier generation and free carrier saturation (when pump fluence above ~10 mJ/cm2) on terahertz generation was investigated. And further with this model, we stated the optimized experimental conditions (incident postion, beam diameter, and pulse duration, etc) for maximum generation efficiency in commonly-used tilted-pulse-front scheme. Red shift of spectrum, spatial distribution "splitting" effects of emitted THz beam, and primilary experimental verification under intense laser excitation are given.
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Abstract
Terahertz (THz) spectroscopic sensing and imaging has identified its potentials in a number of areas such as standoff security screening at portals, explosive detection at battle fields, bio-medical research, and so on. With these needs, the development of an intense and broadband THz source has been a focus of THz research. In this work, we report an intense (~10 mW) and ultra-broadband (~150 THz) THz to infrared (IR) source with a Gaussian wavefront, emitted from nano-pore-structured metallic thin films with femtosecond laser pulse excitation. The underlying mechanism has been proposed as thermal radiation. In addition, an intense coherent THz signal was generated through the optical rectification process simultaneously with the strong thermal signal. This unique feature opens up new avenues in biomedical research.
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21
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Ochi Y, Nagashima K, Maruyama M, Tsubouchi M, Yoshida F, Kohno N, Mori M, Sugiyama A. Yb:YAG thin-disk chirped pulse amplification laser system for intense terahertz pulse generation. OPTICS EXPRESS 2015; 23:15057-15064. [PMID: 26072862 DOI: 10.1364/oe.23.015057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have developed a 1 kHz repetition picosecond laser system dedicated for intense terahertz (THz) pulse generation. The system comprises a chirped pulse amplification laser equipped with a Yb:YAG thin-disk amplifier. At room temperature, the Yb:YAG thin-disk regenerative amplifier provides pulses having energy of over 10 mJ and spectral bandwidth of 1.2 nm. The pulse duration achieved after passage through a diffraction grating pair compressor was 1.3 ps. By employing this picosecond laser as a pump source, THz pulses having a peak frequency of 0.3 THz and 4 µJ of energy were generated by means of optical rectification in an Mg-doped LiNbO3 crystal.
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22
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Lu X, Wan R, Wang G, Zhang T, Zhang W. Giant and tunable electric field enhancement in the terahertz regime. OPTICS EXPRESS 2014; 22:27001-27006. [PMID: 25401850 DOI: 10.1364/oe.22.027001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A novel array of slits design combining the nano-slit grating and dielectric-metal is proposed to obtain giant and tunable electric field enhancement in the terahertz regime. The maximum amplitude of electric field is more than 6000 times larger than that of the incident electric field. It is found that the enhancement depends primarily on the stripe and nano-slits width of grating, as well as the thickness of spacer layer. This property is particularly beneficial for the realization of ultra-sensitive nanoparticles detection and nonlinear optics in the terahertz range, such as the second harmonic generation (SHG).
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23
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Fülöp JA, Ollmann Z, Lombosi C, Skrobol C, Klingebiel S, Pálfalvi L, Krausz F, Karsch S, Hebling J. Efficient generation of THz pulses with 0.4 mJ energy. OPTICS EXPRESS 2014; 22:20155-20163. [PMID: 25321225 DOI: 10.1364/oe.22.020155] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Efficient generation of THz pulses with high energy was demonstrated by optical rectification of 785-fs laser pulses in lithium niobate using tilted-pulse-front pumping. The enhancement of conversion efficiency by a factor of 2.4 to 2.7 was demonstrated up to 186 μJ THz energy by cryogenic cooling of the generating crystal and using up to 18.5 mJ/cm2 pump fluence. Generation of THz pulses with more than 0.4 mJ energy and 0.77% efficiency was demonstrated even at room temperature by increasing the pump fluence to 186 mJ/cm2. The spectral peak is at about 0.2 THz, suitable for charged-particle manipulation.
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24
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Li C, Cui YQ, Zhou ML, Du F, Li YT, Wang WM, Chen LM, Sheng ZM, Ma JL, Lu X, Zhang J. Role of resonance absorption in terahertz radiation generation from solid targets. OPTICS EXPRESS 2014; 22:11797-11803. [PMID: 24921301 DOI: 10.1364/oe.22.011797] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The interaction of 100-fs laser pulses with solid targets at laser intensities 10(16)-10(18)W/cm(2) has been investigated experimentally by simultaneous measurements of terahertz (THz) and second harmonic signals. THz yield at the front side of the target, which rises from the self-organized transient electron currents along the target surface, is found scaling linearly with the laser intensity basically. Measurements of specularly reflected light spectrum show clear evidence of resonance absorption. The positive effects of resonance absorption on surface current and THz radiation generation have been confirmed by two-dimensional (2D) particle-in-cell (PIC) simulations and angular-dependent experiments, respectively.
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25
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Baek IH, Kang BJ, Jeong YU, Rotermund F. Diffraction-Limited High-Power Single-Cycle Terahertz Pulse Generation in Prism-Cut LiNbO3for Precise Terahertz Applications. ACTA ACUST UNITED AC 2014. [DOI: 10.3807/josk.2014.18.1.060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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26
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Vicario C, Monoszlai B, Lombosi C, Mareczko A, Courjaud A, Fülöp JA, Hauri CP. Pump pulse width and temperature effects in lithium niobate for efficient THz generation. OPTICS LETTERS 2013; 38:5373-5376. [PMID: 24322261 DOI: 10.1364/ol.38.005373] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a study on THz generation in lithium niobate pumped by a powerful and versatile Yb:CaF(2) laser. The unique laser system delivers transform-limited pulses of variable duration (0.38-0.65 ps) with pulse energies up to 15 mJ and center wavelength of 1030 nm. From previous theoretical investigations, it is expected that such laser parameters are ideally suited for efficient THz generation. Here, we present experimental results on both the conversion efficiency and the THz spectral shape for variable pump pulse durations and for different crystal temperatures, down to 25 K. We experimentally verify the optimum pump parameters for the most efficient and broadband THz generation.
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27
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Gopal A, Singh P, Herzer S, Reinhard A, Schmidt A, Dillner U, May T, Meyer HG, Ziegler W, Paulus GG. Characterization of 700 μJ T rays generated during high-power laser solid interaction. OPTICS LETTERS 2013; 38:4705-4707. [PMID: 24322111 DOI: 10.1364/ol.38.004705] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Laser-produced solid density plasmas are well-known as table-top sources of electromagnetic radiation. Recent studies have shown that energetic broadband terahertz pulses (T rays) can also be generated from laser-driven compact ion accelerators. Here we report the measurement of record-breaking T-Ray pulses with energies no less than 0.7 mJ. The terahertz spectrum has been characterized for frequencies ranging from 0.1-133 THz. The dependence of T-Ray yield on incident laser energy is linear and shows no tendencies of saturation. The noncollinear emission pattern and the high yield reveal that the T rays are generated by the transient field at the rear surface of the solid target.
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28
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Gopal A, Herzer S, Schmidt A, Singh P, Reinhard A, Ziegler W, Brömmel D, Karmakar A, Gibbon P, Dillner U, May T, Meyer HG, Paulus GG. Observation of gigawatt-class THz pulses from a compact laser-driven particle accelerator. PHYSICAL REVIEW LETTERS 2013; 111:074802. [PMID: 23992071 DOI: 10.1103/physrevlett.111.074802] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Indexed: 06/02/2023]
Abstract
We report the observation of subpicosecond terahertz (T-ray) pulses with energies ≥460 μJ from a laser-driven ion accelerator, thus rendering the peak power of the source higher even than that of state-of-the-art synchrotrons. Experiments were performed with intense laser pulses (up to 5×10(19) W/cm(2)) to irradiate thin metal foil targets. Ion spectra measured simultaneously showed a square law dependence of the T-ray yield on particle number. Two-dimensional particle-in-cell simulations show the presence of transient currents at the target rear surface which could be responsible for the strong T-ray emission.
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Affiliation(s)
- A Gopal
- Institute of Optics and Quantumelectronics, Friedrich-Schiller-Universität Jena, Jena, Germany.
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29
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A magnetic non-reciprocal isolator for broadband terahertz operation. Nat Commun 2013; 4:1558. [PMID: 23463001 PMCID: PMC3615378 DOI: 10.1038/ncomms2572] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Accepted: 02/04/2013] [Indexed: 11/16/2022] Open
Abstract
A Faraday isolator is an electromagnetic non-reciprocal device, a key element in photonics. It is required to shield electromagnetic sources against the effect of back-reflected light, as well as to limit the detrimental effect of back-propagating spontaneous emissions. A common isolator variant, the circulator, is widely used to obtain a complete separation between forward- and backward-propagating waves, thus enabling the realization of a desired transfer function in reflection only. Here we demonstrate a non-reciprocal terahertz Faraday isolator, operating on a bandwidth exceeding one decade of frequency, a necessary requirement to achieve isolation with the (few-cycle) pulses generated by broadband sources. The exploited medium allows a broadband rotation, up to 194°/T, obtained using a SrFe12O19 terahertz-transparent permanent magnet. This in turn enables the design of a stand-alone complete terahertz isolator without resorting to an external magnetic field bias, as opposed to all the optical isolators realized so far. Faraday isolators prevent back reflection of light through photonic systems, and are widespread at optical frequencies. Shalaby et al. show that the permanent magnet SrFe12O19 can be used to generate a broadband rotation with low dispersion, and build an isolator suitable for short terahertz pulses.
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30
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Kunitski M, Richter M, Thomson MD, Vredenborg A, Wu J, Jahnke T, Schöffler M, Schmidt-Böcking H, Roskos HG, Dörner R. Optimization of single-cycle terahertz generation in LiNbO3 for sub-50 femtosecond pump pulses. OPTICS EXPRESS 2013; 21:6826-6836. [PMID: 23546064 DOI: 10.1364/oe.21.006826] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We compare different tilted-pulse-front pumping schemes for single-cycle THz generation in LiNbO(3) crystals both theoretically and experimentally in terms of conversion efficiency. The conventional setup with a single lens as an imaging element has been found to be highly inefficient in the case of sub-50 fs pump pulses, mainly due to the resulting chromatic aberrations. These aberrations are avoided in the proposed new setup, which employs two concave mirrors in a Keplerian telescope arrangement as the imaging sequence. This partially compensates spherical aberrations and results in a ca. six times higher conversion efficiency in the case of 35-fs optical pump pulse duration compared to the single-lens setup. A THz field strength of 60 kV/cm was obtained using 0.5 mJ pump pulses. The divergence of the THz beam has been found experimentally to depend on the pump imaging scheme employed.
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Affiliation(s)
- Maksim Kunitski
- Institut für Kernphysik, Goethe Universität Frankfurt am Main, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
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31
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Bakunov MI, Tsarev MV, Mashkovich EA. Terahertz difference-frequency generation by tilted amplitude front excitation. OPTICS EXPRESS 2012; 20:28573-28585. [PMID: 23263095 DOI: 10.1364/oe.20.028573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
To circumvent a velocity mismatch between optical pump and terahertz waves in electro-optic crystals, we propose to use dual-wavelength optical beams tilted with respect to their planes of equal amplitude. The tilt is achieved by transmission of a dual-wavelength laser beam through a diffraction grating placed on the crystal boundary. The proposed technique extends optical rectification of tilted-front femtosecond laser pulses to difference-frequency generation with longer (nanosecond) pulses. Our analysis of the technique for LiNbO(3) pumped at 1.3 μm and GaAs pumped at 1.55 μm shows its efficiency.
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Affiliation(s)
- M I Bakunov
- University of Nizhny Novgorod, Nizhny Novgorod 603950, Russia.
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32
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Avetisyan Y, Tonouchi M. Terahertz generation in quasi-phase-matching structure formed by a phase mask. OPTICS LETTERS 2012; 37:4155-4157. [PMID: 23027310 DOI: 10.1364/ol.37.004155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
It is theoretically shown that application of a phase mask in optical rectification scheme is equivalent to spatial modulation of the crystal's nonlinear coefficient in cross-section plane of the laser beam. It allows using the technique of quasi-phase-matching for efficient noncollinear terahertz (THz) generation by using high-power wide-aperture optical beam. According to calculations, the linewidth of THz generation can be varied from 10 GHz to a few THz by changing the optical beam size. It is shown that the frequency of THz generation can be also tuned by building the image of the phase mask in the crystal with variable magnification.
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Affiliation(s)
- Yuri Avetisyan
- Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
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33
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Sharma G, Al-Naib I, Hafez H, Morandotti R, Cooke DG, Ozaki T. Carrier density dependence of the nonlinear absorption of intense THz radiation in GaAs. OPTICS EXPRESS 2012; 20:18016-18024. [PMID: 23038349 DOI: 10.1364/oe.20.018016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We study the carrier density dependence of nonlinear terahertz (THz) absorption due to field-induced intervalley scattering in photoexcited GaAs using the optical-pump/THz-probe technique. The intervalley scattering in GaAs is strongly dependent on the photo-carrier density. As the carrier density is increased from 1 × 10(17) to 4.7 × 10(17) cm(-3), the nonlinear absorption bleaching increases. However, if the carrier density is increased further above 4.7 × 10(17) cm(-3), the trend reverses and the bleaching is reduced. The initial increase in absorption bleaching is because, unlike low THz field, high THz field experiences intervalley scattering and nonparabolicity of the conduction band. On the other hand, a simple electron transport model shows that the reduction in intervalley scattering is mainly due to the increase in the electron-hole scattering rate with the increase in the carrier density. This increase in the electron-hole scattering rate limits the maximum kinetic energy attainable by the electrons and thus reduces the observed nonlinear absorption.
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Affiliation(s)
- G Sharma
- INRS-EMT, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
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34
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Li C, Zhou ML, Ding WJ, Du F, Liu F, Li YT, Wang WM, Sheng ZM, Ma JL, Chen LM, Lu X, Dong QL, Wang ZH, Lou Z, Shi SC, Wei ZY, Zhang J. Effects of laser-plasma interactions on terahertz radiation from solid targets irradiated by ultrashort intense laser pulses. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:036405. [PMID: 22060511 DOI: 10.1103/physreve.84.036405] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 05/16/2011] [Indexed: 05/31/2023]
Abstract
Interactions of 100-fs laser pulses with solid targets at intensities of 10(18) W/cm(2) and resultant terahertz (THz) radiation are studied under different laser contrast ratio conditions. THz emission is measured in the specular reflection direction, which appears to decrease as the laser contrast ratio varies from 10(-8) to 10(-6). Correspondingly, the frequency spectra of the reflected light are observed changing from second harmonic dominant, three-halves harmonic dominant, to vanishing of both harmonics. Two-dimensional particle-in-cell simulation also suggests that this observation is correlated with the plasma density scale length change. The results demonstrate that the THz emission is closely related to the laser-plasma interaction processes. The emission is strong when resonance absorption is a key feature of the interaction, and becomes much weaker when parametric instabilities dominate.
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Affiliation(s)
- Chun Li
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190, China
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35
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Fülöp JA, Pálfalvi L, Hoffmann MC, Hebling J. Towards generation of mJ-level ultrashort THz pulses by optical rectification. OPTICS EXPRESS 2011; 19:15090-7. [PMID: 21934870 DOI: 10.1364/oe.19.015090] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Optical rectification of ultrashort laser pulses in LiNbO3 by tilted-pulse-front excitation is a powerful way to generate near single-cycle terahertz (THz) pulses. Calculations were carried out to optimize the output THz peak electric field strength. The results predict peak electric field strengths on the MV/cm level in the 0.3-1.5 THz frequency range by using optimal pump pulse duration of about 500 fs, optimal crystal length, and cryogenic temperatures for reducing THz absorption in LiNbO3. The THz electric field strength can be increased further to tens of MV/cm by focusing. Using optimal conditions together with the contact grating technique THz pulses with 100 MV/cm focused electric field strength and energies on the tens-of-mJ scale are feasible.
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Affiliation(s)
- József András Fülöp
- Department of Experimental Physics, University of Pécs, Ifjúság ú 6, 7624 Pécs, Hungary.
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36
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Ropagnol X, Morandotti R, Ozaki T, Reid M. THz pulse shaping and improved optical-to-THz conversion efficiency using a binary phase mask. OPTICS LETTERS 2011; 36:2662-2664. [PMID: 21765501 DOI: 10.1364/ol.36.002662] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We demonstrate improved optical-to-terahertz (THz) conversion efficiency and THz pulse shaping from an interdigitated GaAs large area photoconductive antenna by using a binary phase mask. The binary phase mask results in a time-delayed excitation of the adjacent antennas, which allows subsequent antennas to produce an additive field, thus resulting in a quasi-single-cycle THz pulse. We demonstrate control over the temporal profile of the THz waveform to maximize optical-to-THz conversion efficiency.
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Affiliation(s)
- Xavier Ropagnol
- INRS-EMT, Advanced Laser Light Source, Université du Québec, Varennes, Québec J3X 1S2, Canada.
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37
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Affiliation(s)
- Jason B. Baxter
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania, 19104, United States
| | - Glenn W. Guglietta
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania, 19104, United States
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38
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Babushkin I, Kuehn W, Köhler C, Skupin S, Bergé L, Reimann K, Woerner M, Herrmann J, Elsaesser T. Ultrafast spatiotemporal dynamics of terahertz generation by ionizing two-color femtosecond pulses in gases. PHYSICAL REVIEW LETTERS 2010; 105:053903. [PMID: 20867920 DOI: 10.1103/physrevlett.105.053903] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Indexed: 05/29/2023]
Abstract
We present a combined theoretical and experimental study of spatiotemporal propagation effects in terahertz (THz) generation in gases using two-color ionizing laser pulses. The observed strong broadening of the THz spectra with increasing gas pressure reveals the prominent role of spatiotemporal reshaping and of a plasma-induced blueshift of the pump pulses in the generation process. Results obtained from (3+1)-dimensional simulations are in good agreement with experimental findings and clarify the mechanisms responsible for THz emission.
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Affiliation(s)
- I Babushkin
- Weierstraß-Institut für Angewandte Analysis und Stochastik, 10117 Berlin, Germany
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39
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Fülöp JA, Pálfalvi L, Almási G, Hebling J. Design of high-energy terahertz sources based on optical rectification. OPTICS EXPRESS 2010; 18:12311-12327. [PMID: 20588357 DOI: 10.1364/oe.18.012311] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Detailed analysis of the tilted-pulse-front pumping scheme used for ultrashort THz pulse generation by optical rectification of femtosecond laser pulses is presented. It is shown that imaging errors in a pulse-front-tilting setup consisting of a grating and a lens can lead to a THz beam with strongly asymmetric intensity profile and strong divergence, thereby limiting applications. Optimized setup parameters are given to reduce such distortions. We also show that semiconductors can offer a promising alternative to LiNbO(3) in high-energy THz pulse generation when pumped at longer wavelengths. This requires tilted-pulse-front pumping, however the small tilt angles allow semiconductors to be easily used in such schemes. Semiconductors can be advantageous for generating THz pulses with high spectral intensity at higher THz frequencies, while LiNbO(3) is better suited to generate THz pulses with very large relative spectral width. By using optimized schemes the upscaling of the energy of ultrashort THz pulses is foreseen.
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Affiliation(s)
- J A Fülöp
- Department of Experimental Physics, University of Pécs, Ifjúságú 6, H-7624 Pécs, Hungary.
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Kawada Y, Yasuda T, Nakanishi A, Takahashi H, Aoshima SI. Single-shot measurement of terahertz temporal waveform using pulse-front tilting by a direct vision dispersion prism. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2009; 80:113703. [PMID: 19947733 DOI: 10.1063/1.3257617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We demonstrated a single-shot measurement of terahertz temporal waveform using pulse-front tilting by a direct vision dispersion prism (DVDP). An advantage of this technique is the simplicity with which an electro-optic terahertz imaging optical system can be changed into a single-shot measurement system by inserting a DVDP in the probe beam path. In this technique, control of the angle of pulse-front tilting is very important. We precisely designed DVDP and measured the angle of the pulse-front tilting by interference measurement. We obtained a terahertz temporal waveform with a single shot with a time window of 3.2 ps.
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Affiliation(s)
- Yoichi Kawada
- Central Research Laboratory, Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita, Hamamatsu City 434-8601, Japan
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Su FH, Blanchard F, Sharma G, Razzari L, Ayesheshim A, Cocker TL, Titova LV, Ozaki T, Kieffer JC, Morandotti R, Reid M, Hegmann FA. Terahertz pulse induced intervalley scattering in photoexcited GaAs. OPTICS EXPRESS 2009; 17:9620-9629. [PMID: 19506611 DOI: 10.1364/oe.17.009620] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Nonlinear transient absorption bleaching of intense few-cycle terahertz (THz) pulses is observed in photoexcited GaAs using opticalpump--THz-probe techniques. A simple model of the electron transport dynamics shows that the observed nonlinear response is due to THz-electric- field-induced intervalley scattering over sub-picosecond time scales as well as an increase in the intravalley scattering rate attributed to carrier heating. Furthermore, the nonlinear nature of the THz pulse transmission at high peak fields leads to a measured terahertz conductivity in the photoexcited GaAs that deviates significantly from the Drude behavior observed at low THz fields, emphasizing the need to explore nonlinear THz pulse interactions with materials in the time domain.
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Affiliation(s)
- F H Su
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada
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Blanchard F, Sharma G, Ropagnol X, Razzari L, Morandotti R, Ozaki T. Improved terahertz two-color plasma sources pumped by high intensity laser beam. OPTICS EXPRESS 2009; 17:6044-6052. [PMID: 19365426 DOI: 10.1364/oe.17.006044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We investigate the intensity dependent spatial drift of two-color plasma based terahertz (THz) sources. A simple scheme that uses an off-axis parabolic mirror is presented to overcome this shifting. In addition, the THz energy and electric field measurements are related via the real time images of the THz spot size.
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Affiliation(s)
- F Blanchard
- INRS-EMT, Advanced Laser Light Source, Université du Québec, Varennes, Québec J3X 1S2, Canada.
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Bodrov SB, Stepanov AN, Bakunov MI, Shishkin BV, Ilyakov IE, Akhmedzhanov RA. Highly efficient optical-to-terahertz conversion in a sandwich structure with LiNbO3 core. OPTICS EXPRESS 2009; 17:1871-1879. [PMID: 19189018 DOI: 10.1364/oe.17.001871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We demonstrate experimentally the efficiency of a recently proposed scheme of terahertz generation based on Cherenkov emission from ultrashort laser pulses in a sandwich structure. The structure has a thin nonlinear core covered with a prism of low terahertz absorption. Using an 8 mm long Si-LiNbO(3)-BK7 structure with a 50 microm thick LiNbO(3) core, we converted 40 microJ, 50 fs Ti:sapphire laser pulses into terahertz pulses of approximately 3 THz bandwidth with a record efficiency of over 0.1%.
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Affiliation(s)
- S B Bodrov
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia.
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