设计并制作了一种光纤微悬臂梁传感器，由于悬臂梁在受迫振动过程中不会产生拉伸变形，与四周固定的圆形密闭薄膜相比，会产生更高的声波灵敏度。采用飞秒激光加工制作微悬臂梁薄膜光纤声波传感器，制备出长宽均为500 μm，厚6 μm的微悬臂梁结构。通过实验得到其反射光谱对比度为8.8 dB，自由光谱范围为7.72 nm，理论计算得光纤法布里-珀罗腔长为155.6 μm。研究结果表明，该光纤声波传感器在2 200 Hz处出现明显的共振峰，对应的声压灵敏度为414 mV/Pa，在300 Hz时有最大的灵敏度675 mV/Pa，与普通硅橡胶薄膜声波传感器相比灵敏度显著提高。理论计算硅橡胶微悬臂梁光纤声波传感器的一阶共振频率为198 Hz，与实验测得的共振频率较为接近。同时悬臂梁传感器的声压灵敏度可达675 mV/Pa，声压响应线性度为0.994。

The Mathieu beam is a typical nondiffracting beam characterized by its propagation invariance and self-reconstruction. These extraordinary properties have given rise to potentialities for applications such as optical communications, optical trapping, and material processing. However, the experimental generation of Mathieu–Gauss beams possessing high quality and compactness is still challenging. In this work, even and helical Mathieu phase plates with different orders m and ellipticity parameters q are fabricated by femtosecond laser two-photon polymerization. The experimentally generated nondiffracting beams are propagation-invariant in several hundred millimeters, which agree with numerical simulations. This work may promote the miniaturization of the application of nondiffracting beams in micronanooptics.

在高速飞行器、航空发动机、核反应堆等**安全和国民经济的重要领域，需要实现1800 ℃以上的高温原位测量。常规石英光纤传感器受限于材料特性，无法在1000 ℃以上高温环境中长期稳定使用。单晶蓝宝石光纤具有极高的熔点（2053 ℃）和较低的传输损耗，是一种良好的高温传感材料。在单晶蓝宝石光纤内部刻写布拉格光栅，可以研制出蓝宝石光纤光栅传感器，具有耐温性能好、测量精度高、便于多点测量等优点，是当前最具发展前景的新型高温传感器件。首先介绍了蓝宝石光纤光栅高温传感器的工作原理和理论模型，接着介绍了利用飞秒激光制备蓝宝石光纤光栅的三种主流技术，包括相位掩模板扫描法、双光束干涉法、直写法，并从制备效率、光谱质量等方面比较了三种技术的优劣，指出飞秒激光直写法是制备蓝宝石光纤光栅高温传感器的最佳手段；然后介绍了蓝宝石光纤光栅的光谱优化方法，包括如何减小光栅光谱带宽和如何降低光谱噪声；进一步介绍了蓝宝石光纤光栅的高温传感特性、封装工艺及高温温度、应变传感应用；最后展望了蓝宝石光纤光栅传感器的未来发展趋势。蓝宝石光纤光栅高温传感器的快速发展和大规模推广应用，必将有助于解决当前我国航空航天、核电等领域重大装备结构健康监测的卡脖子难题。

提出了一种用于超低温环境的微纳光纤非本征法布里-珀罗干涉仪压力传感器。单模光纤端面通过飞秒激光刻蚀出微孔，与无芯光纤熔接形成密闭的法珀腔。通过将无芯光纤切割、研磨等步骤，制作出微纳光纤压力传感器。利用飞秒激光微加工，可以加工出不同孔径的微孔及不同厚度的膜片，得到不同灵敏度及测量压力范围的压力传感器。实验结果表明，提出的传感器在-196 ℃、0~5 MPa的压力范围内表现出良好的线性度，压力升高和降低过程中腔长-压力灵敏度分别为110.33 nm/MPa和110.68 nm/MPa。该传感器能够满足超低温环境下的压力测量需求。

The femtosecond laser has been an efficient tool for optical fiber high temperature sensor construction. Here, we review the progress of optical fiber high temperature sensors based on femtosecond laser fabricated fiber gratings and various types of fiber in-line interferometers in silica fibers and sapphire fibers.

Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits. Benefiting from their high optical confinement and miniaturized footprints, waveguide structures established based on crystalline materials, particularly, are opening exciting possibilities and opportunities in photonic chips by facilitating their on-chip integration with different functionalities and highly compact photonic circuits. Femtosecond-laser-direct writing (FsLDW), as a true three-dimensional (3D) micromachining and microfabrication technology, allows rapid prototyping of on-demand waveguide geometries inside transparent materials via localized material modification. The success of FsLDW lies not only in its unsurpassed aptitude for realizing 3D devices but also in its remarkable material-independence that enables cross-platform solutions. This review emphasizes FsLDW fabrication of waveguide structures with 3D layouts in dielectric crystals. Their functionalities as passive and active photonic devices are also demonstrated and discussed.