We present computational and experimental investigations of the beam folding properties and fringe suppression capabilities in monolithic toroidal multipass cells (MPCs) when combined with absorption masks. Coherent field simulations based on the Fresnel-Huygens theory were performed to understand the effect of multiple field truncations in such an optically semi-unstable mirror arrangement. The explicit numerical calculation of the radiation field at each reflection allows detailed optimization and performance analysis. We experimentally verified the evolving irradiance distributions and identified optimal initial field configurations. Furthermore, we suggest a proxy to estimate the noise level for specific initial conditions. These insights pave the way to a better optical performance and, thus, to even more lightweight and compact designs of this MPC type.
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http://dx.doi.org/10.1364/OL.42.003137 | DOI Listing |
Sci Bull (Beijing)
January 2025
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore; Centre for Disruptive Photonic Technologies, The Photonics Institute, Nanyang Technological University, Singapore 639798, Singapore. Electronic address:
Bound states in the continuum (BICs) are notable in photonics for their infinite Q factors. Perturbed BICs, or quasi-BICs (QBICs), have finite but ultra-high Q factors, enabling external coupling. So far, most studies have focused on the momentum-space properties of BICs and QBICs, with few discussions on their properties in real space.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming 650500, China.
The failure mode of thin-walled C-channel beams typically manifests as premature local buckling of the compression flange, leading to insufficient utilization of material strength in both the flange and the web. To address this issue, this study adopts the approach of increasing the number of bends to reinforce the flange and adding V-shaped stiffeners in the middle of the web to reduce the width-to-thickness ratio of the plate elements, thereby delaying local buckling and allowing for greater plastic deformation. However, the challenge lies in the irregular cross-sectional shape and complex buckling patterns.
View Article and Find Full Text PDFThe cross talk and power consumption of the 2 × 2 optical switch is a key metric in the design of large-scale photonic integrated circuits (PICs). We build a theoretical model of a 2 × 2 Mach-Zehnder interferometer (MZI) optical switch, taking into account both imbalances in the arm loss and the coupler splitting ratio. The splitting ratio imbalance requirement for a given switch cross talk is summarized, which provides a guideline for the switch design.
View Article and Find Full Text PDFBiochim Biophys Acta Gen Subj
February 2025
Department of Physics, Savitribai Phule Pune University, Pune 411007, India.
Understanding the folding and unfolding mechanism of the protein is not only crucial in applications like biomedical, pharmaceutical, tissue engineering but also to the food industry. In the present study, an electron beam with 6 MeV energy derived from the Microtron accelerator was utilized to irradiate the aqueous solution of bovine serum albumin (BSA) at fluences of 5 × 10 and 10 × 10 e/cm. The control and irradiated BSA solutions were analyzed using UV-visible and FTIR spectroscopy.
View Article and Find Full Text PDFZoolog Sci
December 2024
Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan,
Planktonic larvae of sessile metazoans select substrates for settlement based on various factors. larvae (Ascidiacea: Phlebobranchia: Ascidiidae) showed a negative preference for nano-scale nipple arrays (dense arrays of papillae-like nanostructures approximately 100 nm in height). To clarify whether ascidian larvae discriminate between nano-structure sizes for substrate selection, three different sizes of periodic nano-folds were fabricated using two-beam interference exposure, and substrate selection assays were performed on the three types of nano-folds and flat surfaces made of the same material.
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