MXene V₂CT_x has great practicability because it is not easy to degrade under ambient conditions. In this paper, a V₂CT_x saturable absorber (SA) was firstly applied to a passively Q-switched (PQS) laser, to the best of our knowledge. The V₂CT_x-SA was prepared by the spin-coating method. The linear absorption of the V₂CT_x-SA in the 1000–2200 nm region and the nonlinear absorption near 2 µm were studied. With the V₂CT_x-SA, a typical PQS operation at 1.94 µm was realized in a Tm:YAlO3 laser. The minimum pulse width produced by the PQS laser was 528 ns, and the peak power, repetition rate, and average output power were 10.06 W, 65.9 kHz, and 350 mW, respectively. Meanwhile, the maximum pulse energy was 6.33 µJ. This work demonstrates that the V₂CT_x can be used as an effective SA to obtain nanosecond pulses with high peak power and high repetition rate simultaneously.

主三反射镜支撑结构是离轴三反生物成像系统研制过程中的关键技术难点之一，为了减少工作环境下主三镜面形变化，满足支撑系统稳定性要求，利用有限元方法对主三镜组件进行了优化设计。首先，根据光学系统设计要求确定了反射镜及其支撑结构的材料和支撑方式。接着，优化布局了反射镜底部3点和侧面6点支撑位置，设计了轻量化镜室结构。根据优化数学模型设计了圆弧悬臂梁式柔性铰链结构，分析了在重力工况下和温度载荷工况下各参数对镜面面形精度的影响。然后，对反射镜支撑组件进行了静力学和热力学仿真分析，分析结果为重力工况下镜面均方根值RMS为1.529 nm，温度变化4 ℃时镜面均方根值RMS为2.426 nm。最后，采用Zygo干涉仪对支撑作用下的主三反射镜和系统波像差进行检测，实测反射镜镜面RMS值为0.025 λ，系统波像差RMS值为0.102 λ(λ=632.8 nm)，基本满足了生物成像系统技术指标（主三镜镜面RMS≤λ/40，系统波像差RMS≤λ/10）要求。