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- 实验方案
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Optimization of Transmitter-Side Signal Rotations in the Presence of Laser Phase Noise
摘要： In this paper, we present a 1050-nm electrically pumped microelectromechanically tunable vertical cavity surface-emitting laser (MEMS-VCSEL) with a record dynamic tuning bandwidth of 63.8 nm, suitable for swept-source optical coherence tomography (SS-OCT) imaging. These devices provide reduced cost and complexity relative to previously demonstrated optically pumped devices by obviating the need for a pump laser and associated hardware. We demonstrate ophthalmic SS-OCT imaging with the electrically-pumped MEMS-VCSEL at a 400 kHz axial scan rate for wide-field imaging of the in vivo human retina over a 12 mm × 12 mm field and for OCT angiography of the macula over 6 mm × 6 mm and 3 mm × 3 mm fields to show retinal vasculature and capillary structure near the fovea. These results demonstrate the feasibility of electrically pumped MEMS-VCSELs in ophthalmic instrumentation, the largest clinical application of OCT. In addition, we estimate that the 3 dB coherence length in air is 225 ± 51 m, far greater than required for ophthalmic SS-OCT and suggestive of other distance ranging applications.
关键词： Medical imaging,tunable lasers,optical coherence tomography,micro and nano opto-electromechanical systems (MOEMS),semiconductor lasers
更新于2025-09-23 15:21:01
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A Fast Multiobjective Optimization Strategy for Single-Axis Electromagnetic MOEMS Micromirrors
摘要： Micro-opto-electro-mechanical (MOEMS) micromirrors are an enabling technology for mobile image projectors (pico-projectors). Low size and low power are the crucial pico-projector constraints. In this work, we present a fast method for the optimization of a silicon single-axis electromagnetic torsional micromirror. In this device, external permanent magnets provide the required magnetic field, and the actuation torque is generated on a rectangular multi-loop coil microfabricated on the mirror plate. Multiple constraints link the required current through the coil, its area occupancy, the operating frequency, mirror suspension length, and magnets size. With only rather general assumptions about the magnetic field distribution and mechanical behavior, we show that a fully analytical description of the mirror electromagnetic and mechanical behavior is possible, so that the optimization targets (the assembly size, comprising the mirror and magnets, and the actuation current) can be expressed as closed functions of the design parameters. Standard multiobjective optimization algorithms can then be used for extremely fast evaluation of the trade-offs among the various optimization targets and exploration of the Pareto frontier. The error caused by model assumptions are estimated by Finite Element Method (FEM) simulations to be below a few percent points from the exact solution.
关键词： MOEMS,micromirrors,magnetic actuation,pico-projectors,Micro-electro-mechanical systems (MEMS),multiobjective optimization
更新于2025-09-23 15:21:01
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Graphene-like Si <sub/>3</sub> N <sub/>3</sub> and Si <sub/>3</sub> N <sub/>4</sub> Nanolayers on Silicon Surface
摘要： In this paper, we present a 1050-nm electrically pumped microelectromechanically tunable vertical cavity surface-emitting laser (MEMS-VCSEL) with a record dynamic tuning bandwidth of 63.8 nm, suitable for swept-source optical coherence tomography (SS-OCT) imaging. These devices provide reduced cost and complexity relative to previously demonstrated optically pumped devices by obviating the need for a pump laser and associated hardware. We demonstrate ophthalmic SS-OCT imaging with the electrically-pumped MEMS-VCSEL at a 400 kHz axial scan rate for wide-field imaging of the in vivo human retina over a 12 mm × 12 mm field and for OCT angiography of the macula over 6 mm × 6 mm and 3 mm × 3 mm fields to show retinal vasculature and capillary structure near the fovea. These results demonstrate the feasibility of electrically pumped MEMS-VCSELs in ophthalmic instrumentation, the largest clinical application of OCT. In addition, we estimate that the 3 dB coherence length in air is 225 ± 51 m, far greater than required for ophthalmic SS-OCT and suggestive of other distance ranging applications.
关键词： Medical imaging,tunable lasers,optical coherence tomography,micro and nano opto-electromechanical systems (MOEMS),semiconductor lasers
更新于2025-09-16 10:30:52
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Quasi-statischer MOEMS-Gitterscanner zum spektralen Durchstimmen eines MIR-Quantenkaskadenlasers
摘要： Broadband tuning of MIR-infrared radiation from 3 to 10 μm (1000 to 3200 wavenumbers) is a very promising way for spectroscopic study of gaseous, liquid, or solid species or intermixtures. We report a new quasi-static micro-optical-electrical-mechanic (MOEMS) grating for spectral tuning of an IR light source based on a quantum cascade laser. This concept unites the advantages of broadband sources with the advantages of coherent laser sources in a miniaturized setup. In contrary to resonant MOEMS device, the quasi-static driving principle allows the scanning with arbitrary trajectories and velocity and thus with potential higher spectral resolution. To stabilize the trajectory the MOEMS device is controlled by integrated position sensors. We report the dynamical characteristics of MOEMS micro-mirror with integrated diffraction grating and experimental results of the tuning of a QCL in the wavelength range from 4150 to 4600 nm.
关键词： quantum cascade laser,IR spectroscopy,MOEMS scanner,diffraction grating,micro-mirror
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 31st International Conference on Microelectronics (MIEL) - Nis, Serbia (2019.9.16-2019.9.18)] 2019 IEEE 31st International Conference on Microelectronics (MIEL) - Arrays of Bowtie Plasmonic Nanoantennas for Field Enhancement in MOEMS
摘要： Many micro(nano)optoelectromechanical systems (MOEMS, NOEMS) require optical (generally, electromagnetic) field localization and concentration. These include for instance photocatalytic microreactors and labs on a chip, where it is necessary to localize optical energy into a fluidic channel. Other examples are chemical and biological sensors. Plasmonics on the other hand ensures field localization down to subwavelength volumes where evanescent fields can be tailored to the shape of minuscule channels in MOEMS and NOEMS. In this work we present a possible approach to the enhancement of optical fields in MOEMS and NOEMS systems where a linear array of plasmonic bowtie structures is used to concentrate the optical field into a dielectric channel. We perform our numerical simulations using the finite element method to analyze field distributions that can be achieved by the use of the bowtie antenna and the possibility to tailor these fields. We also analyze the influence of the shape of the coupled tips of bowties to the field distribution and frequency dispersion. We conclude that arrays of plasmonic bowties could be a promising candidate for optically assisted micro and nanofluidics.
关键词： field enhancement,bowtie nanoantennas,MOEMS,NOEMS,plasmonics,finite element method
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Advances in MOEMS-Based External Cavity QCLs
摘要： The combination of broadband quantum cascade lasers (QCLs) with a micro-electro-mechanical system (MOEMS) scanner with integrated diffraction grating as a wavelength-selective and optical feedback providing element enables the realization of compact, portable and robust spectroscopy systems. As previously showed [1–2], such MOEMS-based external cavity (EC)-QCLs configurations lead to measurement times as low as ~1 millisecond per QCL-tuning range (hundreds of cm-1) while eliminating the need of homodyne detection systems, such as lock-in electronics. Also non-resonant (quasistatic) MOEMS grating scanners providing scan rates of tens of Hz as well as static setting of arbitrary wavelengths are possible, keeping the advantage of using small MOEMS footprints, ruggedness, and low power consumption. Here we review our latest developments in MOEMS-based EC-QCLs made by Fraunhofer IAF and IPMS. We present a miniaturized, non-resonant MOEMS EC-QCL that allows scan frequencies of few tens of Hz (as well as static operation) together with an excellent wavelength reproducibility within a small and compact device. Static-controllable MOEMS EC-QCLs are of high interest for spectroscopy applications that require both arbitrary tuning speeds (e.g. large time constants as in photothermal or photoacoustic spectroscopy) and discrete wavelength tuning. Such tuning speeds are not achievable with resonantly-driven MOEMS scanners, as their mechanical resonance frequency remains >120 Hz. Both requirements can be well fulfilled with static-controllable MOEMS EC-QCLs independently of the QCL gain bandwidth characteristics. We also present a resonantly-driven continuous wave (cw) MOEMS EC-QCL with cavity-length control to enable fast high-resolution fast spectroscopy over a spectral range of >100 cm-1 and discuss our progress towards a dispersion-free beam spot radius for MOEMS EC-QCLs and our approach to operate MOEMS EC-QCLs in a permanent low-noise regime.
关键词： wavelength tuning,QCL,external cavity,spectroscopy,MOEMS
更新于2025-09-11 14:15:04