The sub-wavelength grating has special characteristics compared to traditional *** to the requirement of the optical communication devices,sub-wavelength grating polarizer was designed based on rigorous coupled-wave t...
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The sub-wavelength grating has special characteristics compared to traditional *** to the requirement of the optical communication devices,sub-wavelength grating polarizer was designed based on rigorous coupled-wave theory(RCWA).The paper analyzes the grating parameters such as the period,depth,fill grove that influence the diffraction efficiency of the grating. Calculation results indicate that the diffraction efficiency of sub-wavelength grating changes with the period,the depth of the grove,fill factor,and shape of the grating. The TM mode diffraction efficiency is more than 95%,and the TE mode diffraction efficiency is less than 5%,the pyramidal sub-wavelength polarizer grating has good performance than others shapes in the optical communication band of *** this paper,we designed this kind of sub-wavelength grating polarizer has great potential applying in optical switching,optical memory,optical detectors and other photo-electronic devices.
Compressed sensing(CS)can recover sparse signals from under-sampled measurements. Recently,we have developed an advanced CS framework—CS with partially known support (PKS)—for photoacoustic computed tomography(PACT)...
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Compressed sensing(CS)can recover sparse signals from under-sampled measurements. Recently,we have developed an advanced CS framework—CS with partially known support (PKS)—for photoacoustic computed tomography(PACT).During the reconstruction,a small part of the nonzero signals' locations in the transformed sparse domain is used as *** reconstructions have been performed with under-sampled in vivo image data of human hands and small *** to PACT with basic CS,PACT with CS-PKS can recover signals using fewer ultrasonic transducer elements and can improve convergence speed, which may ultimately enable high-speed,low-cost PACT for various biomedical applications. In addition,ultrasonic-array-based optical-resolution photoacoustic computed tomography (OR-PACT),providing micrometer resolution at high speed,has opened up new opportunities for studying microvascular *** this work,we have further developed our CS-PKS reconstruction strategy for *** with conventional back-projection reconstruction,the CS-PKS strategy was shown to produce high-quality in vivo OR-PACT images with three-fold less measurement data,which can be leveraged to improve the data acquisition speed and costs of OR-PACT systems.
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