1
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Wang Y, Zhong L, Lau KY, Han X, Yang Y, Hu J, Firstov S, Chen Z, Ma Z, Tong L, Chiang KS, Tan D, Qiu J. Precise mode control of laser-written waveguides for broadband, low-dispersion 3D integrated optics. LIGHT, SCIENCE & APPLICATIONS 2024; 13:130. [PMID: 38834560 DOI: 10.1038/s41377-024-01473-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 04/25/2024] [Accepted: 05/08/2024] [Indexed: 06/06/2024]
Abstract
Three-dimensional (3D) glass chips are promising waveguide platforms for building hybrid 3D photonic circuits due to their 3D topological capabilities, large transparent windows, and low coupling dispersion. At present, the key challenge in scaling down a benchtop optical system to a glass chip is the lack of precise methods for controlling the mode field and optical coupling of 3D waveguide circuits. Here, we propose an overlap-controlled multi-scan (OCMS) method based on laser-direct lithography that allows customizing the refractive index profile of 3D waveguides with high spatial precision in a variety of glasses. On the basis of this method, we achieve variable mode-field distribution, robust and broadband coupling, and thereby demonstrate dispersionless LP21-mode conversion of supercontinuum pulses with the largest deviation of <0.1 dB in coupling ratios on 210 nm broadband. This approach provides a route to achieve ultra-broadband and low-dispersion coupling in 3D photonic circuits, with overwhelming advantages over conventional planar waveguide-optic platforms for on-chip transmission and manipulation of ultrashort laser pulses and broadband supercontinuum.
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Affiliation(s)
- Yuying Wang
- College of Optical Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Lijing Zhong
- Institute of Light+X Science and Technology, College of Information Science and Engineering, Ningbo University, 315211, Ningbo, China.
| | - Kuen Yao Lau
- School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 215006, Suzhou, China
| | - Xuhu Han
- College of Optical Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Yi Yang
- College of Optical Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Jiacheng Hu
- College of Optical Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Sergei Firstov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Dianov Fiber Optics Research Center, 38 Vavilov str., Moscow, 119333, Russia
| | - Zhi Chen
- Zhejiang Lab, 311121, Hangzhou, China.
- College of Materials Science and Engineering, Key Laboratory of Advanced Materials of Yunnan Province, Kunming University of Science and Technology, 650093, Kunming, Yunnan, China.
| | - Zhijun Ma
- Zhejiang Lab, 311121, Hangzhou, China.
| | - Limin Tong
- College of Optical Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Kin Seng Chiang
- Department of Electrical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Dezhi Tan
- Zhejiang Lab, 311121, Hangzhou, China.
- School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China.
| | - Jianrong Qiu
- College of Optical Science and Engineering, Zhejiang University, 310027, Hangzhou, China.
- Institute of Light+X Science and Technology, College of Information Science and Engineering, Ningbo University, 315211, Ningbo, China.
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2
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Afsary N, Tasnim F, Rasel MOF, Ishigure T. Polarization manipulation on step-index composite polymer beam splitters for photonics circuitry. Heliyon 2024; 10:e24585. [PMID: 38317907 PMCID: PMC10838734 DOI: 10.1016/j.heliyon.2024.e24585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 02/07/2024] Open
Abstract
This paper presents composite beam splitters realized with polymer materials for developing photonic integrated circuits. We used organic-inorganic hybrid polymer materials to form this composite beam splitter realized with step-index (SI) core profiles. We used the alternating direction implicit technique of the Rsoft CAD BeamPROP solver to design and analyze these beam splitters. We successfully examined and manipulated the beam splitter's polarization dependency to obtain a 99% output efficiency with a 50:50 splitting ratio. The SI beam splitter exhibits an excess loss of 0.014 dB. When we apply polarized light in this beam splitter, the excess loss increases to 2 dB, and this loss gradually decreases as the angle of incident light increases. The excess loss reduces to 0.05 dB at the 31-degree angles of the incident polarized light. We also investigated the crosstalk of this beam splitter by varying the wavelength, and it is evident that the lowest crosstalk is -19.77 dB at the polarized angle of 31°.
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Affiliation(s)
- Noor Afsary
- Physics Discipline, Khulna University, Khulna, 9208, Bangladesh
| | - Fariha Tasnim
- Physics Discipline, Khulna University, Khulna, 9208, Bangladesh
| | | | - Takaaki Ishigure
- Faculty of Science and Technology, Keio University, Yokohama, 223-8522, Japan
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3
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Paiè P, Calisesi G, Candeo A, Comi A, Sala F, Ceccarelli F, De Luigi A, Veglianese P, Muhlberger K, Fokine M, Valentini G, Osellame R, Neil M, Bassi A, Bragheri F. Structured-light-sheet imaging in an integrated optofluidic platform. LAB ON A CHIP 2023; 24:34-46. [PMID: 37791882 DOI: 10.1039/d3lc00639e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Heterogeneity investigation at the single-cell level reveals morphological and phenotypic characteristics in cell populations. In clinical research, heterogeneity has important implications in the correct detection and interpretation of prognostic markers and in the analysis of patient-derived material. Among single-cell analysis, imaging flow cytometry allows combining information retrieved by single cell images with the throughput of fluidic platforms. Nevertheless, these techniques might fail in a comprehensive heterogeneity evaluation because of limited image resolution and bidimensional analysis. Light sheet fluorescence microscopy opened new ways to study in 3D the complexity of cellular functionality in samples ranging from single-cells to micro-tissues, with remarkably fast acquisition and low photo-toxicity. In addition, structured illumination microscopy has been applied to single-cell studies enhancing the resolution of imaging beyond the conventional diffraction limit. The combination of these techniques in a microfluidic environment, which permits automatic sample delivery and translation, would allow exhaustive investigation of cellular heterogeneity with high throughput image acquisition at high resolution. Here we propose an integrated optofluidic platform capable of performing structured light sheet imaging flow cytometry (SLS-IFC). The system encompasses a multicolor directional coupler equipped with a thermo-optic phase shifter, cylindrical lenses and a microfluidic network to generate and shift a patterned light sheet within a microchannel. The absence of moving parts allows a stable alignment and an automated fluorescence signal acquisition during the sample flow. The platform enables 3D imaging of an entire cell in about 1 s with a resolution enhancement capable of revealing sub-cellular features and sub-diffraction limit details.
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Affiliation(s)
- Petra Paiè
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
| | - Gianmaria Calisesi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
| | - Alessia Candeo
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
| | - Andrea Comi
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
| | - Federico Sala
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
| | - Francesco Ceccarelli
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
| | - Ada De Luigi
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Via Mario Negri 2, Milano, 20156, Italy
| | - Pietro Veglianese
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Via Mario Negri 2, Milano, 20156, Italy
| | - Korbinian Muhlberger
- Department of Applied Physics, KTH Royal Institute of Technology, Roslagstullsbacken 21, Stockholm, 11421, Sweden
| | - Michael Fokine
- Department of Applied Physics, KTH Royal Institute of Technology, Roslagstullsbacken 21, Stockholm, 11421, Sweden
| | - Gianluca Valentini
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
| | - Roberto Osellame
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
| | - Mark Neil
- Physics Department, Imperial College London, Prince Consort Road, London, SW7 2BB, UK
| | - Andrea Bassi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
| | - Francesca Bragheri
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
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4
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Giordani T, Wagner R, Esposito C, Camillini A, Hoch F, Carvacho G, Pentangelo C, Ceccarelli F, Piacentini S, Crespi A, Spagnolo N, Osellame R, Galvão EF, Sciarrino F. Experimental certification of contextuality, coherence, and dimension in a programmable universal photonic processor. SCIENCE ADVANCES 2023; 9:eadj4249. [PMID: 37922346 PMCID: PMC10624346 DOI: 10.1126/sciadv.adj4249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 10/02/2023] [Indexed: 11/05/2023]
Abstract
Quantum superposition of high-dimensional states enables both computational speed-up and security in cryptographic protocols. However, the exponential complexity of tomographic processes makes certification of these properties a challenging task. In this work, we experimentally certify coherence witnesses tailored for quantum systems of increasing dimension using pairwise overlap measurements enabled by a six-mode universal photonic processor fabricated with a femtosecond laser writing technology. In particular, we show the effectiveness of the proposed coherence and dimension witnesses for qudits of dimensions up to 5. We also demonstrate advantage in a quantum interrogation task and show it is fueled by quantum contextuality. Our experimental results testify to the efficiency of this approach for the certification of quantum properties in programmable integrated photonic platforms.
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Affiliation(s)
- Taira Giordani
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy
| | - Rafael Wagner
- International Iberian Nanotechnology Laboratory (INL), Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
- Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Chiara Esposito
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy
| | - Anita Camillini
- International Iberian Nanotechnology Laboratory (INL), Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
- Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Francesco Hoch
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy
| | - Gonzalo Carvacho
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy
| | - Ciro Pentangelo
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
| | - Francesco Ceccarelli
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
| | - Simone Piacentini
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
| | - Andrea Crespi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
| | - Nicolò Spagnolo
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy
| | - Roberto Osellame
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
| | - Ernesto F. Galvão
- International Iberian Nanotechnology Laboratory (INL), Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
- Instituto de Física, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Niterói, RJ, 24210-340, Brazil
| | - Fabio Sciarrino
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy
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5
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Dinkelaker AN, Smarzyk S, Nayak AS, Piacentini S, Corrielli G, Osellame R, Pedretti E, Roth MM, Madhav K. Six-telescope integrated optics beam combiner fabricated using ultrafast laser inscription for J- and H-band astronomy. APPLIED OPTICS 2023; 62:7596-7610. [PMID: 37855467 DOI: 10.1364/ao.499135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 09/15/2023] [Indexed: 10/20/2023]
Abstract
We have built and characterized, to our knowledge, the first six-telescope discrete beam combiner (DBC) for stellar interferometry in the astronomical J-band. It is the DBC with the largest number of beam combinations and was manufactured using ultrafast laser inscription in borosilicate glass, with a throughput of ≈56%. For calibration of the visibility-to-pixel matrix, we use a two-input Michelson interferometer and extract the complex visibility. A visibility amplitude of 1.05 and relative precision of 2.9% and 3.8% are extracted for 1328 nm and 1380 nm, respectively. Broadband (≤40n m) characterization is affected by dispersion but shows similar performance.
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6
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Benedicto D, Martín JC, Dias-Ponte A, Solis J, Vallés JA. An Integrated Pump-Controlled Variable Coupler Fabricated by Ultrafast Laser Writing. MICROMACHINES 2023; 14:1370. [PMID: 37512681 PMCID: PMC10384359 DOI: 10.3390/mi14071370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/28/2023] [Accepted: 07/02/2023] [Indexed: 07/30/2023]
Abstract
The design and fabrication of a integrated symmetric directional coupler dependent o the pumping power and operating at a 1534 nm wavelength is reported. The twin-core waveguide was inscribed into Er3+/Yb3+ co-doped phosphate glass by a femtosecond laser direct writing technique. By optical pumping, the coupling ratio can be modulated due to the changes induced in the refractive index of the material. The experimental results demonstrated that the coupling ratio can be tuned continuously from 100/0 to 50/50 by increasing the pump's power from 0 to 350 mW. The developed twin-core coupler has promising applications for on-chip all-optical signal processing and communication systems.
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Affiliation(s)
- David Benedicto
- Departamento de Física Aplicada, Instituto de Investigación en Ingeniería de Aragón (I3A), Facultad de Ciencias, Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain
| | - Juan C Martín
- Departamento de Física Aplicada, Instituto de Investigación en Ingeniería de Aragón (I3A), Facultad de Ciencias, Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain
| | - Antonio Dias-Ponte
- Laser Processing Group, Institute of Optics (IO-CSIC), Serrano 121, 28006 Madrid, Spain
| | - Javier Solis
- Laser Processing Group, Institute of Optics (IO-CSIC), Serrano 121, 28006 Madrid, Spain
| | - Juan A Vallés
- Departamento de Física Aplicada, Instituto de Investigación en Ingeniería de Aragón (I3A), Facultad de Ciencias, Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain
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7
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Wang YD, Zhang ZY, Chen Y, Sun YK, Li YC, Tian ZN, Ren XF, Chen QD, Guo GC. Arbitrarily rotated optical axis waveguide induced by a trimming line. OPTICS LETTERS 2023; 48:3063-3066. [PMID: 37262281 DOI: 10.1364/ol.493410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 05/18/2023] [Indexed: 06/03/2023]
Abstract
Rotated optical axis waveguides can facilitate on-chip arbitrary wave-plate operations, which are crucial tools for developing integrated universal quantum computing algorithms. In this paper, we propose a unique technique based on femtosecond laser direct writing technology to fabricate arbitrarily rotated optical axis waveguides. First, a circular isotropic main waveguide with a non-optical axis was fabricated using a beam shaping method. Thereafter, a trimming line was used to create an artificial stress field near the main waveguide to induce a rotated optical axis. Using this technique, we fabricated high-performance half- and quarter-wave plates. Subsequently, high-fidelity (97.1%) Pauli-X gate operation was demonstrated via quantum process tomography, which constitutes the basis for the full manipulation of on-chip polarization-encoded qubits. In the future, this work is expected to lead to new prospects for polarization-encoded information in photonic integrated circuits.
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8
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Wang YD, Li ZZ, Li YC, Duan YZ, Wang LC, Yu YH, Chen QD. Ultralow birefringent glass waveguide fabricated by femtosecond laser direct writing. OPTICS LETTERS 2023; 48:554-557. [PMID: 36723529 DOI: 10.1364/ol.481072] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 12/14/2022] [Indexed: 06/18/2023]
Abstract
Optical waveguides prepared by femtosecond laser direct writing have birefringent properties, which can affect polarization encoding and entanglement on chips. Here, we first propose a shape-stress dual compensation fabrication scheme to decrease birefringence. Ultralow birefringent waveguides (1 × 10-9) were obtained by controlling the cross sectional shape of the main waveguide and adjusting the position of the auxiliary lines. In addition, we prepared polarization-independent directional coupler and demonstrated the evolution of polarization-independent waveguide array with different polarized light. In the future, ultralow birefringent waveguides will be widely applied in polarization encoding and entangled quantum photonic integrated circuits.
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9
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Cui E, Wan Z, Ke C, Wu C, Wang D, Lei C. Flexible and efficient fabrication of a terahertz absorber by single-step laser direct writing. OPTICS EXPRESS 2022; 30:42944-42955. [PMID: 36523004 DOI: 10.1364/oe.468753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/30/2022] [Indexed: 06/17/2023]
Abstract
Laser direct writing (LDW) is a promising candidate for the fabrication of all-dielectric THz absorbers for its high flexibility and material compatibility. However, multi-step processing or multi-layer materials are required to compensate for the nonideal features of LDW to realize good absorption performance. To further explore the potential of LDW in flexible and cost-effective THz absorber fabrication, in this work, we demonstrate a design method of THz absorbers fully considering and utilizing the characteristics of laser processing. Specifically, we first numerically analyze that by properly combining basic structures processed by single-step LDW, good and adjustable absorption performance can be achieved on a single-layer substrate. Then we experimentally fabricate THz absorbers by processing periodic composite structures, which are combined by grooves and circular holes, on single-layer doped silicon using LDW. Experimental results show that our method can fabricate THz absorbers at a speed of 3.3 mm2/min with an absorptivity above 90% over a broadband of 1.8-3 THz. Our method provides a promising solution for the flexible and efficient fabrication of all-dielectric broadband THz absorbers.
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10
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Calvarese M, Paiè P, Candeo A, Calisesi G, Ceccarelli F, Valentini G, Osellame R, Gong H, Neil M, Bragheri F, Bassi A. Integrated optical device for Structured Illumination Microscopy. OPTICS EXPRESS 2022; 30:30246-30259. [PMID: 36242132 DOI: 10.1364/oe.466225] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/08/2022] [Indexed: 06/16/2023]
Abstract
Structured Illumination Microscopy (SIM) is a key technology for high resolution and super-resolution imaging of biological cells and molecules. The spread of portable and easy-to-align SIM systems requires the development of novel methods to generate a light pattern and to shift it across the field of view of the microscope. Here we show a miniaturized chip that incorporates optical waveguides, splitters, and phase shifters, to generate a 2D structured illumination pattern suitable for SIM microscopy. The chip creates three point-sources, coherent and controlled in phase, without the need for further alignment. Placed in the pupil of a microscope's objective, the three sources generate a hexagonal illumination pattern on the sample, which is spatially translated thanks to thermal phase shifters. We validate and use the chip, upgrading a commercial inverted fluorescence microscope to a SIM setup and we image biological sample slides, extending the resolution of the microscope.
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11
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Albiero R, Pentangelo C, Gardina M, Atzeni S, Ceccarelli F, Osellame R. Toward Higher Integration Density in Femtosecond-Laser-Written Programmable Photonic Circuits. MICROMACHINES 2022; 13:mi13071145. [PMID: 35888962 PMCID: PMC9320504 DOI: 10.3390/mi13071145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/15/2022] [Accepted: 07/17/2022] [Indexed: 11/21/2022]
Abstract
Programmability in femtosecond-laser-written integrated circuits is commonly achieved with the implementation of thermal phase shifters. Recent work has shown how such phase shifters display significantly reduced power dissipation and thermal crosstalk with the implementation of thermal isolation structures. However, the aforementioned phase shifter technology is based on a single gold film, which poses severe limitations on integration density and circuit complexity due to intrinsic geometrical constraints. To increase the compactness, we propose two improvements to this technology. Firstly, we fabricated thermal phase shifters with a photolithography process based on two different metal films, namely (1) chromium for microheaters and (2) copper for contact pads and interconnections. Secondly, we developed a novel curved isolation trench design that, along with a state-of-the-art curvature radius, allows for a significant reduction in the optical length of integrated circuits. As a result, curved Cr-Cu phase shifters provide a compact footprint with low parasitic series resistance and no significant increase in power dissipation (∼38 mW) and thermal crosstalk (∼20%). These results pave the way toward the fabrication of femtosecond-laser-written photonic circuits with a steep increase in terms of layout complexity.
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Affiliation(s)
- Riccardo Albiero
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy; (R.A.); (C.P.); (M.G.)
- Istituto di Fotonica e Nanotecnologie-Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci 32, 20133 Milano, Italy; (F.C.); (R.O.)
| | - Ciro Pentangelo
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy; (R.A.); (C.P.); (M.G.)
- Istituto di Fotonica e Nanotecnologie-Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci 32, 20133 Milano, Italy; (F.C.); (R.O.)
| | - Marco Gardina
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy; (R.A.); (C.P.); (M.G.)
| | - Simone Atzeni
- Istituto di Fotonica e Nanotecnologie-Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci 32, 20133 Milano, Italy; (F.C.); (R.O.)
- Correspondence:
| | - Francesco Ceccarelli
- Istituto di Fotonica e Nanotecnologie-Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci 32, 20133 Milano, Italy; (F.C.); (R.O.)
| | - Roberto Osellame
- Istituto di Fotonica e Nanotecnologie-Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci 32, 20133 Milano, Italy; (F.C.); (R.O.)
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12
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Laser-Assisted Etching of EagleXG Glass by Irradiation at Low Pulse-Repetition Rate. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12030948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Femtosecond laser micromachining is becoming an established technique for the fabrication of complex three-dimensional structures in glass. The combination of laser writing and chemical etching increases the technique versatility by allowing the fabrication of hollow structures within the bulk material. The possibility to encompass both optical and fluidic components in a single substrate allows us to realize optofluidic devices usable in several application fields. Here, we present new investigations of laser-assisted etching in Eagle XG glass showing good etching conditions at low repetition rates, where thermal effects can be neglected, and low irradiation speeds, which allow for complex microchannel network formation.
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13
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Strategies for improved temporal response of glass-based optical switches. Sci Rep 2022; 12:239. [PMID: 34997131 PMCID: PMC8742015 DOI: 10.1038/s41598-021-04218-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 12/15/2021] [Indexed: 11/08/2022] Open
Abstract
We present an optimization of the dynamics of integrated optical switches based on thermal phase shifters. These devices have been fabricated in the volume of glass substrates by femtosecond laser micromachining and are constituted by an integrated Mach–Zehnder interferometer and a superficial heater. Simulations, surface micromachining and innovative layouts allowed us to improve the temporal response of the optical switches down to a few milliseconds. In addition, taking advantage of an electrical pulse shaping approach where an optimized voltage signal is applied to the heater, we proved a switching time as low as 78 µs, about two orders of magnitude shorter with respect to the current state of the art of thermally-actuated optical switches in glass.
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Phase-Type Fresnel Zone Plate with Multi-Wavelength Imaging Embedded in Fluoroaluminate Glass Fabricated via Ultraviolet Femtosecond Laser Lithography. MICROMACHINES 2021; 12:mi12111362. [PMID: 34832775 PMCID: PMC8617647 DOI: 10.3390/mi12111362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 12/02/2022]
Abstract
Herein, we report a novel optical glass material, fluoroaluminate (AlF3) glass, with excellent optical transmittance from ultraviolet to infrared wavelength ranges, which provides more options for application in optical devices. Based on its performance, the phase-type Fresnel zone plate (FZP) by ultraviolet femtosecond (fs) laser-inscribed lithography is achieved, which induces the refractive index change by fs-laser tailoring. The realization of ultraviolet fs-laser fabrication inside glass can benefit from the excellent optical performance of the AlF3 glass. Compared with traditional surface-etching micro-optical elements, the phase-type FZP based on AlF3 glass exhibits a clear and well-defined geometry and presents perfect environmental suitability without surface roughness problems. Additionally, optical focusing and multi-wavelength imaging can be easily obtained. Phase-type FZP embedded in AlF3 glass has great potential applications in the imaging and focusing in glass-integrated photonics, especially for the ultraviolet wavelength range.
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Nayak AS, Labadie L, Sharma TK, Piacentini S, Corrielli G, Osellame R, Gendron É, Buey JTM, Chemla F, Cohen M, Bharmal NA, Bardou LF, Staykov L, Osborn J, Morris TJ, Pedretti E, Dinkelaker AN, Madhav KV, Roth MM. First stellar photons for an integrated optics discrete beam combiner at the William Herschel Telescope. APPLIED OPTICS 2021; 60:D129-D142. [PMID: 34263868 DOI: 10.1364/ao.423881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 06/13/2021] [Indexed: 06/13/2023]
Abstract
We present the first on-sky results of a four-telescope integrated optics discrete beam combiner (DBC) tested at the 4.2 m William Herschel Telescope. The device consists of a four-input pupil remapper followed by a DBC and a 23-output reformatter. The whole device was written monolithically in a single alumino-borosilicate substrate using ultrafast laser inscription. The device was operated at astronomical H-band (1.6 µm), and a deformable mirror along with a microlens array was used to inject stellar photons into the device. We report the measured visibility amplitudes and closure phases obtained on Vega and Altair that are retrieved using the calibrated transfer matrix of the device. While the coherence function can be reconstructed, the on-sky results show significant dispersion from the expected values. Based on the analysis of comparable simulations, we find that such dispersion is largely caused by the limited signal-to-noise ratio of our observations. This constitutes a first step toward an improved validation of the DBC as a possible beam combination scheme for long-baseline interferometry.
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Shankar Nayak A, Poletti T, Sharma TK, Madhav K, Pedretti E, Labadie L, Roth MM. Chromatic response of a four-telescope integrated-optics discrete beam combiner at the astronomical L band. OPTICS EXPRESS 2020; 28:34346-34361. [PMID: 33182907 DOI: 10.1364/oe.405896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 10/19/2020] [Indexed: 06/11/2023]
Abstract
We show the results of simulation and experimental study of a 4-telescope zig-zag discrete beam combiner (DBC) for long-baseline stellar interferometry working at the astronomical L band (3 - 4 µm) under the influence of a narrow bandwidth light source. Following Saviauk et al. (2013), we used a quasi-monochromatic visibility-to-pixel matrix (V2PM) for retrieving the complex coherence functions from simulated and experimentally measured power at the output of the device. Simulation and coefficient of determination (R2) measurements show that we are able to retrieve the visibility amplitudes with >95 % accuracy of our chromatic model source up to a bandwidth of 100 nm centred at 3.5 µm. We characterized a DBC manufactured by 3D ultra-fast laser inscription (ULI) written on gallium lanthanum sulphate (GLS). Experimental results showed retrieval of visibility amplitude with an accuracy of 80-90 % at 69 nm bandwidth, validating our simulation. The standard deviation of experimental phase residuals are between 0.1-0.4 rad, which shows that the retrieval procedure is sufficient to get good quality images, where phase perturbations of less than 1 rad are expected under good seeing conditions for astronomical applications.
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Will T, Guan J, Salter PS, Booth MJ. Trimming laser-written waveguides through overwriting. OPTICS EXPRESS 2020; 28:28006-28016. [PMID: 32988081 DOI: 10.1364/oe.400623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/06/2020] [Indexed: 06/11/2023]
Abstract
Femtosecond laser direct writing is widely used to create waveguide circuits for optical processing in applications including communications, astrophotonics, simulation and quantum information processing. The properties of these waveguide circuits can be sensitive to the fabrication conditions, meaning that noticeable variability can be present in nominally identical manufactured components. One potential solution to this problem is the use of device trimming, whereby additional laser fabrication is applied to optimise the optical properties of a device based upon measurement feedback. We show how this approach can be used in the manufacture of directional couplers by overwriting the laser-written structure to alter the coupling ratios.
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Fernandez TT, Gross S, Arriola A, Privat K, Withford MJ. Revisiting ultrafast laser inscribed waveguide formation in commercial alkali-free borosilicate glasses. OPTICS EXPRESS 2020; 28:10153-10164. [PMID: 32225607 DOI: 10.1364/oe.387790] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/10/2020] [Indexed: 06/10/2023]
Abstract
Alkali-free borosilicate glasses are one of the most used dielectric platforms for ultrafast laser inscribed integrated photonics. Femtosecond laser written waveguides in commercial Corning Eagle 2000, Corning Eagle XG and Schott AF32 glasses were analyzed. They were studied in depth to disclose the dynamics of waveguide formation. We believe that the findings presented in this paper will help bridge one of the major and important gaps in understanding the ultrafast light-matter interaction with alkali-free boroaluminosilicate glass. It was found that the waveguides are formed mainly due to structural and elemental reorganization upon laser inscription. Aluminum along with alkaline earth metals were found to be responsible for the densification and silicon being the exchanging element to form a rarefied zone. Strong affinity towards alkaline earth elements to form the densified zone for waveguides written with high feed rate (>200 mm/min) were identified and explained. Finally we propose a plausible solution to form positive refractive index change waveguides in different glasses based on current and previous reports.
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Wang CY, Gao J, Jiao ZQ, Qiao LF, Ren RJ, Feng Z, Chen Y, Yan ZQ, Wang Y, Tang H, Jin XM. Integrated measurement server for measurement-device-independent quantum key distribution network. OPTICS EXPRESS 2019; 27:5982-5989. [PMID: 30876192 DOI: 10.1364/oe.27.005982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 12/26/2018] [Indexed: 06/09/2023]
Abstract
Quantum key distribution (QKD), harnessing quantum physics and optoelectronics, may promise unconditionally secure information exchange in theory. Recently, theoretical and experimental advances in measurement-device-independent (MDI)-QKD have successfully closed the physical back door in detection terminals. However, the issues of scalability, stability, cost and loss prevent QKD systems from widespread application in practice. Here, we propose and experimentally demonstrate a solution to build a star-topology quantum access network with an integrated server. By using femtosecond laser direct writing techniques, we construct integrated circuits for all the elements of Bell state analyzer together and are able to integrate 10 such analyzer structures on a single photonic chip. The measured high-visibility Bell state analysis suggests the integrated server as a promising platform for the practical application of MDI-QKD network.
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Wang CY, Gao J, Jin XM. On-chip rotated polarization directional coupler fabricated by femtosecond laser direct writing. OPTICS LETTERS 2019; 44:102-105. [PMID: 30645553 DOI: 10.1364/ol.44.000102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 11/20/2018] [Indexed: 06/09/2023]
Abstract
We present a rotated polarization directional coupler (RPDC) on a photonic chip. We demonstrate a double-track approach to modify the distribution of the refractive index between adjacent tracks and form a single waveguide with an arbitrary birefringent optical axis. We construct a RPDC with the two axis-rotated waveguides coupled in a strong regime. The obtained extinction ratios on average are about 16 dB and 20 dB for the corresponding orthogonal polarizations. We perform reconstruction of the Stokes vector to test the projection performance of our RPDC, and observe the average fidelities up to 98.1% and 96.0% for the perfectly initialized states in 0° and 45° RPDCs, respectively.
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