High-resolution multi-color printing relies upon pixelated optical nanostructures, which is crucial to promote color display by producing nonbleaching colors, yet requires simplicity in fabrication and dynamic switching. Antimony trisulfide (Sb₂S₃) is a newly rising chalcogenide material that possesses prompt and significant transition of its optical characteristics in the visible region between amorphous and crystalline phases, which holds the key to color-varying devices. Herein, we proposed a dynamically switchable color printing method using Sb₂S₃-based stepwise pixelated Fabry-Pérot (FP) cavities with various cavity lengths. The device was fabricated by employing a direct laser patterning that is a less time-consuming, more approachable, and low-cost technique. As switching the state of Sb₂S₃ between amorphous and crystalline, the multi-color of stepwise pixelated FP cavities can be actively changed. The color variation is due to the profound change in the refractive index of Sb₂S₃ over the visible spectrum during its phase transition. Moreover, we directly fabricated sub-50 nm nano-grating on ultrathin Sb₂S₃ laminate via microsphere 800-nm femtosecond laser irradiation in far field. The minimum feature size can be further decreased down to ~45 nm (λ/17) by varying the thickness of Sb₂S₃ film. Ultrafast switchable Sb₂S₃ photonic devices can take one step toward the next generation of inkless erasable papers or displays and enable information encryption, camouflaging surfaces, anticounterfeiting, etc. Importantly, our work explores the prospects of rapid and rewritable fabrication of periodic structures with nano-scale resolution and can serve as a guideline for further development of chalcogenide-based photonics components.

设计并制作了一种高灵敏度且制作简单的聚甲基丙烯酸甲酯（Polymethyl Methacrylate，PMMA）微球与单模光纤复合的湿度传感器。该光纤湿度传感器由PMMA微球与单模光纤构成。由于在微球中形成了法布里-珀罗腔，当外界环境湿度升高时，PMMA微球吸收水分子体积膨胀，导致法布里-珀罗腔的腔长增长，使得传感器干涉光谱的波峰（谷）发生红移，从而实现湿度传感。对所制作传感器的湿度响应、稳定性和重复性等进行了实验研究，实验结果表明：在30%~80%湿度范围内，该湿度传感器的灵敏度达173.36 pm/%RH，波长漂移随相对湿度变化呈良好的线性关系，其线性度达0.992 26，且具有良好的稳定性和重复性。该PMMA微球与单模光纤复合的湿度传感器具有灵敏度高、结构简单、无需镀膜且易于制作的优点。

针对在多腔型法布里-珀罗传感器中难以提取动态信号的问题，提出了一种用于多腔型法布里-珀罗传感器的三波长解调技术。该解调技术使用放大自发辐射光源和三个固定中心波长的宽带光纤滤波器，使干涉现象仅发生在多腔型光纤法布里-珀罗传感器的短腔中，以此提取较短腔的三个干涉信号。建立了校正算法和反正切算法来提取振动信号。实验结果表明，该解调技术成功提取了频率为1 kHz、峰峰值幅度为2.6 μm的振动信号。解调速度为500 kHz，解调分辨率为0.25 nm。该解调技术具有系统紧凑、成本低、速度快、鲁棒性高等优点，在多腔型法布里-珀罗传感器方面有巨大的潜力。

为降低窄带宽超材料吸收器（Metamaterial Absorber，MA）制造成本的同时拓宽其应用领域，本文基于时域有限差分法利用介质材料设计出双波长窄带宽介质MA，其由Au衬底、SiO₂介质层和Si介质非对称光栅构成。经模拟计算发现，本文提出的双波长窄带宽介质MA在λ₁=1.20852 μm和λ₂=1.23821 μm具有超高吸收效率，而且FWHM也分别只有0.735 nm和0.077 nm。MA在λ₁实现窄带宽吸收主要是因为光在SiO₂层形成了法布里-珀罗(Fabry-Pérot, FP)腔共振，而MA在λ₂实现窄带宽吸收主要是由于入射光在介质非对称光栅中形成了导模共振效应。经理论计算可知，通过改变MA的结构参数可对其吸收特性产生较为显著的影响。

We demonstrate two ultra-stable laser systems at 1064 nm by independently stabilizing two 10-cm-long Fabry–Pérot cavities. The reference cavities are on a cubic spacer, which is rigidly mounted for both low sensitivity to environmental vibration and ability for transportation. By comparing against an independent ultra-stable laser at 578 nm via an optical frequency comb, the 1064 nm lasers are measured to have frequency instabilities of 6 × 10^?16 at 1 s averaging time.

Orbital angular momentum (OAM) mode division provides a promising solution to push past the already exhausted available degrees of freedom available in conventional optical communications. Nevertheless, the practical deployment of OAM within a free-space optical (FSO) communications system is still hampered by a major challenge, namely that OAM-based FSO links are vulnerable to disturbances. Though several techniques, such as using various non-diffraction beams and multiple transmit–receive apertures, are proposed to alleviate the influence of disturbances, these techniques significantly reduce the performance with regard to combating single fading for spatial blockages of the laser beam by obstructions. In this work, we initially demonstrate that a Fabry-Pérot resonant cavity has the ability to implement OAM mode healing, even for a blocking percentage of over 50%. Consequently, the proposed method will expand the use of OAM in the FSO secure communications and quantum encryption fields.