Nonlinear absorption at 1.064 and 1.535 microm wavelengths by two photon and free carrier absorption processes in undoped and Fe doped InP has been investigated. Using picosecond and nanosecond duration lasers, a self-consistent set of the two photon and free carrier absorption coefficients are experimentally obtained through nonlinear transmission measurements for the first time. Reduced carrier recombination lifetime caused a decrease in nonlinear absorption of nanosecond duration laser pulses in Fe doped samples.
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http://dx.doi.org/10.1364/oe.17.008741 | DOI Listing |
Biomed Opt Express
January 2025
Department of Electronic Engineering, Maynooth University, Maynooth, Co. Kildare, Ireland.
Optical diffraction tomography enables label-free, 3D refractive index (RI) imaging of biological samples. We present a novel, cost-effective approach to ODT that employs a modular design incorporating a self-reference holographic capture module. This two-part system consists of an illumination module and a capture module that can be seamlessly integrated with any life-science microscope using an automated alignment protocol.
View Article and Find Full Text PDFBiomed Opt Express
January 2025
Warsaw University of Technology, Institute of Micromechanics and Photonics, 8 Sw. A. Boboli St., 02-525 Warsaw, Poland.
A fair comparison of multiple live cell cultures requires examining them under identical environmental conditions, which can only be done accurately if all cells are prepared simultaneously and studied at the same time and place. This contribution introduces a multiplexed lensless digital holographic microscopy system (MLS), enabling synchronous, label-free, quantitative observation of multiple live cell cultures with single-cell precision. The innovation of this setup lies in its ability to robustly compare the behaviour, i.
View Article and Find Full Text PDFWe demonstrate a compact ring-assisted Mach-Zehnder interferometer (RAMZI)-based silicon photonic interleaver with a 400 GHz free spectral range (FSR), featuring flat passbands exceeding a spectral range of 50 nm. Additionally, we introduce a novel, to the best of our knowledge, add-on structure and tuning method enabling automated compensation for fabrication imperfections, precise shaping of the RAMZI flat-top passbands, and alignment with Kerr comb lines. Experimental results have shown successful interleaving of eight channels of distributed-feedback (DFB) lasers as well as a 200 GHz Kerr comb, both achieving an extinction ratio of approximately 20 dB.
View Article and Find Full Text PDFWhen observing chip-to-free-space light beams from silicon photonics (SiPh) to free space, manual adjustment of camera lens is often required to obtain a focused image of the light beams. In this Letter, we demonstrated an auto-focusing system based on the you-only-look-once (YOLO) model. The trained YOLO model exhibits high classification accuracy of 99.
View Article and Find Full Text PDFA circular waveguide-fed conical horn antenna is fabricated using two-photon lithography (TPL) and integrated with a spintronic terahertz radiation emitter source to provide enhanced radiation directivity. In comparison to the bare terahertz radiation source, incorporating the antenna permits a spectral density gain up to 20.5 dB.
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