Brillouin microscopy, which maps the elastic modulus from the frequency shift of scattered light, has evolved to a faster speed for the investigation of rapid biomechanical changes. Impulsive stimulated Brillouin scattering (ISBS) spectroscopy has the potential to speed up measurement through the resonant amplification interaction from pulsed excitation and time-domain continuous detection. However, significant progress has not been achieved due to the limitation in signal-to-noise ratio (SNR) and the corresponding need for excessive averaging to maintain high spectral precision. Moreover, the limited spatial resolution also hinders its application in mechanical imaging. Here, by scrutinizing the SNR model, we design a high-speed ISBS microscope through multi-parameter optimization including phase, reference power, and acquisition time. Leveraging this, with the further assistance of the Matrix Pencil method for data processing, three-dimensional mechanical images are mapped under multiple contrast mechanisms for a millimeter-scale polydimethylsiloxane pattern immersed in methanol, enabling the identification of these two transparent materials without any contact or labeling. Our experimental results demonstrate the capability to maintain high spectral precision and resolution at a sub-millisecond integration time for one pixel. With a two-order improvement in the speed and a tenfold improvement in the spatial resolution over the state-of-the-art systems, this method makes it possible for ISBS microscopes to sensitively investigate rapid mechanical changes in time and space.

Modern scintillator-based radiation detectors require silicon photomultipliers (SiPMs) with photon detection efficiency higher than 40% at 420 nm, possibly extended to the vacuum ultraviolet (VUV) region, single-photon time resolution (SPTR) < 100 ps, and dark count rate (DCR) < 150 kcps/mm². To enable single-photon time stamping, digital electronics and sensitive microcells need to be integrated in the same CMOS substrate, with a readout frame rate higher than 5 MHz for arrays extending over a total area up to 4 mm × 4 mm. This is challenging due to the increasing doping concentrations at low CMOS scales, deep-level carrier generation in shallow trench isolation fabrication, and power consumption, among others. The advances at 350 and 110 nm CMOS nodes are benchmarked against available SiPMs obtained in CMOS and commercial customized technologies. The concept of digital multithreshold SiPMs with a single microcell readout is finally reported, proposing a possible direction toward fully digital scintillator-based radiation detectors.

Virtual reality (VR) and augmented reality (AR) are revolutionizing our lives. Near-eye displays are crucial technologies for VR and AR. Despite the rapid advances in near-eye display technologies, there are still challenges such as large field of view, high resolution, high image quality, natural free 3D effect, and compact form factor. Great efforts have been devoted to striking a balance between visual performance and device compactness. While traditional optics are nearing their limitations in addressing these challenges, ultra-thin metasurface optics, with their high light-modulating capabilities, may present a promising solution. In this review, we first introduce VR and AR near-eye displays, and then briefly explain the working principles of light-modulating metasurfaces, review recent developments in metasurface devices geared toward near-eye display applications, delved into several advanced natural 3D near-eye display technologies based on metasurfaces, and finally discuss about the remaining challenges and future perspectives associated with metasurfaces for near-eye display applications.

从光学工程应用的角度对全国云量情况进行了研究，重点分析了全国陆地主要地区云量总体平均情况、冷暖半年、昼夜变化等三个方面云量历史数据，研究结果表明：全国陆地主要地区总云量和低云量分布区域基本呈北少南多的情况；冷暖半年云量分布有较明显的差别，暖半年云量高于冷半年的站点区域占全国较大面积；昼夜云量分布区别主要体现在西部地区白天低云低值区会有中高云存在。在云量总体平均情况、冷暖半年、昼夜变化的分析基础上进而讨论了全国云量区域的分级情况，结果表明适合光学工程应用的1级区主要分在北方。结果有助于了解全国适于开展光学工程应用的区域，并可为进一步研究云量对光学工程应用产生的定量影响提供参考。