The performance and reliability of ferroelectric thin films at temperatures around a few Kelvin are critical for their application in cryo-electronics. In this work, TiN/Hf_0.5Zr_0.5O₂/TiN capacitors that are free from the wake-up effect are investigated systematically from room temperature (300 K) to cryogenic temperature (30 K). We observe a consistent decrease in permittivity (ε_r) and a progressive increase in coercive electric field (E_c) as temperatures decrease. Our investigation reveals exceptional stability in the double remnant polarization (2P_r) of our ferroelectric thin films across a wide temperature range. Specifically, at 30 K, a 2P_r of 36 μC/cm² under an applied electric field of 3.0 MV/cm is achieved. Moreover, we observed a reduced fatigue effect at 30 K in comparison to 300 K. The stable ferroelectric properties and endurance characteristics demonstrate the feasibility of utilizing HfO₂ based ferroelectric thin films for cryo-electronics applications.

长波红外差分干涉仪在低温工况下会因光学元件受到非均匀应力作用产生干涉条纹的畸变，从而降低干涉仪系统性能。本文为解决低温工况干涉条纹弯曲畸变问题，基于长波红外差分干涉仪光机系统进行了干涉条纹畸变影响因素分析，结合光-机-热耦合分析方法，对干涉仪系统低温工作状态进行仿真。随后设计了针对影响条纹畸变的关键元件——光栅元件的低温微应力动态稳定支撑安装结构，结构优化后的光栅表面面形均方根（Root Mean Square， RMS）值为3.89×10^-2 nm，面形峰谷值（Peak to Valley， PV）值为2.21×10^-1 nm，分别较优化前初始系统的分析结果减小了5个数量级，系统仿真干涉条纹畸变小于1个探测器像元。全系统低温验证试验表明，优化结构可有效抑制干涉条纹畸变，畸变量小于2个探测器像元，试验与仿真计算结果一致性较好，验证了优化分析方法的有效性。该优化方案对提升反射式光学系统结构低温稳定性，提高系统工作能力有较大意义和价值。

大阵列BIB探测器由于其高量子效率和低暗电流而成为广泛的研究对象，特别是在空间应用方向。如2021年发射的詹姆斯韦伯太空望远镜，它已经进行了许多重要的天文观测。一个稳定、高效、轻量化的液氦温区低温系统对BIB探测器的运行至关重要。氦节流制冷机可取代传统的大容积液氦杜瓦，能满足空间液氦温区的制冷要求。为了同时提高4.2 K的制冷量并减轻重量，提出了一种0.3 W@4.2 K的大冷量轻量化的4.2 K低温制冷系统。并且在现有0.1 W@4.1 K制冷量的低温系统上进行实验，验证了该系统的设计方法。在不同的冷却温度区采用不同的冷却方法，以实现冷却的高效性和轻便性。开发了一个新的集成斯特林制冷机，在80 K时提供高效的一级预冷，制冷量为15 W，重量仅为4.5 kg；二级预冷采用主动活塞调相的15 K脉管制冷机，制冷量为0.9 W。此多级低温制冷系统通过耦合氦气JT循环，可以在4.2 K时提供0.3 W的制冷量，输入功低于1.8 kW。此系统将为正在快速发展的红外天文观测所需的空间BIB探测器提供保障。

利用溶剂热法制备了六角相NaYF₄∶20%Yb，2%Er@NaYF₄@NaYbF₄∶0.5%Tm@NaYF₄多层核壳结构稀土掺杂上转换纳米粒子，研究其在低温场（10~295 K）及980 nm激发下分别来自于Er³⁺的绿色与红色以及Tm³⁺的蓝色发光的上转换发光性质。结果显示，绿光强度随温度升高呈现出先增后降的变化趋势，而蓝光强度随温度升高呈现热衰减的趋势。本工作利用发光强度比的测温方法实现了精准的温度测量，相对灵敏度可达3.2%·K^-1。并通过改变外层发光壳层的厚度调节发光强度比，进一步应用于低温场光学防伪。

为了确保低温辐射计测量准确度，开展了低温辐射计光功率修正因子的研究。介绍了低温辐射计测试系统光路结构和光功率的测量过程。分析了影响低温辐射计光电加热等效替代的四个主要因素。利用搭建的影响因子测试装置，对布儒斯特窗口透过率、杂散光和黑体腔吸收率三个影响因子进行了测试；采用有限元分析方法，对光电加热不等效性因子进行了仿真计算。测试和仿真计算了自主研制低温辐射计光电加热等效替代修正因子，结果显示，布儒斯特窗口在632.8 nm处的透过率为0.996 817，杂散光修正因子为0.999 013，黑体腔吸收率为0.999 950，光电不等效性修正因子为1.009 240±0.000 010。该研究结果可用于低温辐射计的修正，对低温辐射计各功能模块的设计、测量不确定度的提高以及低温辐射计的研制具有一定参考价值。

We propose and demonstrate a cryogenic thermo-optic (TO) modulator in x-cut thin-film lithium niobate (TFLN) with an NbN superconducting heater. Compared to a conventional metal heating electrode, a fast and energy-efficient modulation is obtained by placing an NbN superconducting heating electrode above the TFLN waveguide. The transition of the NbN superconducting electrode between superconducting and normal states turns the heating and cooling processes from continuous to discontinuous change. Thus, the energy consumption during the modulation process is reduced proportionally. The rise/fall time of the proposed device is 22 µs/15 µs, which has been the fastest response time reported in TFLN thermo-optic modulators so far. The presented TO modulator can easily be used at cryogenic temperatures and has great potential for applications in cryogenic optoelectronics.

This study focuses on generating and manipulating squeezed states with two external oscillators coupled by an InP HEMT operating at cryogenic temperatures. First, the small-signal nonlinear model of the transistor at high frequency at 5 K is analyzed using quantum theory, and the related Lagrangian is theoretically derived. Subsequently, the total quantum Hamiltonian of the system is derived using Legendre transformation. The Hamiltonian of the system includes linear and nonlinear terms by which the effects on the time evolution of the states are studied. The main result shows that the squeezed state can be generated owing to the transistor’s nonlinearity; more importantly, it can be manipulated by some specific terms introduced in the nonlinear Hamiltonian. In fact, the nonlinearity of the transistors induces some effects, such as capacitance, inductance, and second-order transconductance, by which the properties of the external oscillators are changed. These changes may lead to squeezing or manipulating the parameters related to squeezing in the oscillators. In addition, it is theoretically derived that the circuit can generate two-mode squeezing. Finally, second-order correlation (photon counting statistics) is studied, and the results demonstrate that the designed circuit exhibits antibunching, where the quadrature operator shows squeezing behavior.

星载长波红外相机工作时需要将整个光学系统的温度降低至−20 °C以下，以减少背景红外辐射的影响。在弱导热连接结构设计的基础上，研制了Ω型柔性遮阳装置，通过直接辐冷方式实现了光学系统的低温设计；研制了鸟笼式三维导热带，实现了主镜筒的均温设计。作为国内首个在空间领域应用的低温光学系统随实践九号B星进行了在轨飞行试验，结果表明，整个光学系统温度可长期保持在−35 °C～−20 °C，主镜筒圆周温度差小于4 °C。该热控设计方法简单有效，可以为类似星载红外光学系统的热设计提供参考。