图 1  激光干涉原理, 通过引力波带来两臂光程差的改变, 得到信号输出

Figure 1.  Principle of laser interferometry, the change in the optical path difference between the two arms due to gravitational waves results in the signal output.

图 2  LISA引力波探测计划^[8]　(a) 3个航天器构成三角形结构, (b) 3个航天器绕着太阳转动

Figure 2.  LISA gravitational wave detection mission^[8]: (a) Three spacecraft form a triangular structure, (b) the three spacecraft orbit around the Sun.

图 3  天琴引力波探测计划的初步概念, 以J0806为参考源, 3艘“天琴号”航天器分别表示为SC1, SC2和SC3, 还显示了赤道平面, 以及天空中朝向J0806的方向^[10]

Figure 3.  Preliminary concept of the TianQin gravitational wave detection mission with J0806 as the reference source. The three “TianQin” spacecraft are denoted as SC1, SC2, and SC3, and the equatorial plane as well as the direction towards J0806 in the sky are also shown^[10].

图 4  LISA计划中惯性传感器敏感探头结构示意图^[7]. 传感电极以绿色显示, 注入电极以红色显示. 它们对检验质量施加5.4 V, 100 kHz的交流偏置, 以便在检验质量上产生0.61 V的交流电位. 同时, 通过在传感电极上施加不同的直流电压组合, 就可以驱动检验质量在内部自由浮动, 且在x轴上执行干涉测量

Figure 4.  Diagram of the inertial sensor sensitive probe structure in the LISA mission^[7]. The sensing electrodes are shown in green, and the injection electrodes are shown in red. They apply a 5.4 V, 100 kHz AC bias to the test mass, resulting in a 0.61 V AC potential on the test mass. Additionally, by applying different combinations of DC voltages to the sensing electrodes, the test mass can be driven to float freely inside and perform interferometry along the x-axis.

图 5  GRACE FO中加速度计的机械核心, 由18 g的超低膨胀材料立方检验质量组成, 周围环绕着3对类似的电极板, 每对电极板控制两个自由度^[18]

Figure 5.  Mechanical core of the accelerometer in GRACE FO, consisting of an 18 g cubic test mass made of ultra-low expansion material, surrounded by three pairs of similar electrode plates, each pair controlling two degrees of freedom^[18].

图 6  电荷管理示意图, 通过光纤引导紫外光照射检验质量表面^[23]

Figure 6.  Schematic diagram of charge management, where ultraviolet light is guided by optical fiber to irradiate the surface of the test mass^[23].

图 7  低压汞灯结构示意图

Figure 7.  Schematic diagram of the low-pressure mercury lamp structure.

图 8  (a)在陀螺仪中测量紫外线产生电流的装置图; (b)采用254 nm紫外光对运转陀螺仪进行电荷控制, 施加+18, –18和0 V的偏置电压^[19]

Figure 8.  (a) Diagram of the device for measuring the current generated by ultraviolet light in a gyroscope; (b) charge control of the operating gyroscope using 254 nm ultraviolet light, applying bias voltages of +18 V, –18 V, and 0 V^[19].

图 9  (a)陀螺仪外形^[26]; (b)紫外电荷管理光源夹具, 该夹具将紫外光引导到其内表面和陀螺仪上^[25]

Figure 9.  (a) Shape of the gyroscope^[26]; (b) ultraviolet charge management light source fixture, which directs ultraviolet light to its inner surface and the gyroscope^[25].

图 10  LPF电荷管理系统^[20]　(a)紫外灯系统; (b)光纤系统; (c)馈通连接器

Figure 10.  LPF charge management system^[20]: (a) Ultraviolet lamp system; (b) optical fiber system; (c) feedthrough connector.

图 11  (a) p型、n型材料能带图; (b) pn结能带图^[30]

Figure 11.  (a) Energy band diagrams for p-type and n-type materials; (b) energy band diagram of a pn junction^[30].

图 12  交流充电管理实验^[31] (a), (c)左边的数字说明了用于控制负电荷和正电荷转移的相位控制, 图中噪声较强的迹线和噪声较小的迹线分别是UV LED和电极的驱动信号; (b), (d)电荷转移的方向

Figure 12.  AC charge management experiment^[31]: (a), (c) Numbers on the left indicate the phase control used for managing negative and positive charge transfer, the traces with stronger and weaker noise correspond to the driving signals of the UV LED and the electrodes, respectively; (b), (d) illustrate the direction of charge transfer.

图 13  (a)扭秤实验装置示意图, 装置由一个悬挂的矩形金涂层硅摆板、一个略大的可移动金涂层铜板和一个金涂层的铝控制电极组成, 通过自动准直仪光学测量摆板的扭转位移, 并利用PID回路控制电极上的电压, 以维持摆板的固定角度, 此外, 图中还标出了用于从摆板移除和添加电子的UV LED和电子枪. (b)摆板充放电实验结果示意图, 横轴表示时间, 纵轴表示摆板上的电荷量^[32]

Figure 13.  (a) Schematic diagram of the torsion balance experimental setup, the setup consists of a suspended rectangular gold-coated silicon vane, a slightly larger movable gold-coated copper plate, and a gold-coated aluminum control electrode, the vane's torsional displacement is measured optically using an auto-collimator, and the voltage on the electrode is controlled via a PID loop to maintain the vane at a fixed angle. Additionally, the UV LED and electron gun used for removing and adding electrons to the vane are indicated in the figure. (b) Schematic diagram of the vane charging and discharging experiment results, with the x-axis representing time and the y-axis representing the charge on the vane^[32].

图 14  (a) UV LED在氮气中的工作寿命测试达到19000 h以上; (b) UV LED在真空中的工作寿命测试达到8000 h以上; (c) UV LED在氮气中运行10500 h后中心波长偏移在2 nm以内^[33]

Figure 14.  (a) UV LED operational lifetime test in nitrogen reaching over 19000 hours; (b) UV LED operational lifetime test in vacuum reaching over 8000 hours; (c) the center wavelength shift of the UV LED after operating for 10500 hours in nitrogen is within 2 nm^[33].

图 15  质子辐射下UV LED测试的实验装置布局(顶视图), 回旋加速器输出质子束, 两个255 nm波长的UV LED被安置于质子束流的路径中, 模拟太空飞行条件, 并实时监测其光输出^[33]

Figure 15.  Experimental setup layout for UV LED testing under proton radiation (top view), a cyclotron accelerates and outputs a proton beam, with two UV LEDs emitting at 255 nm placed in the path of the proton beam to simulate spaceflight conditions, and their light output is monitored in real-time^[33].

图 16  质子辐照前后UV LED发射光谱测量, 影响度为2×10¹² 质子/cm², 中心波长255 nm, 无偏移^[33]

Figure 16.  UV LED emission spectra measurements before and after proton irradiation, with a dose of 2 × 10¹² protons/cm², the center wavelength is 255 nm, with no shift^[33].

图 17  UV LED测试前、热真空循环后、震动后、热循环后(测试后)的数据采集^[34]　(a)电流随电压变化情况; (b)光功率随电流变化情况; (c)光谱变化情况

Figure 17.  Data collected of the UV LED before testing, after thermal vacuum cycling, after vibration, and after thermal cycling (post-testing) are shown^[34]: (a) Current versus voltage; (b) optical power versus current; (c) spectral changes.

图 18  在交流电荷控制方式下使用浮动探针测量的检验质量电位, 电势是相对于固定在地面上的系统外壳来测量的, 入射紫外功率为10 μW, 调制频率为100 Hz, 占空比为50%, 偏置为3.0 Vpp, 对地的防护质量电容为17 pF^[34]

Figure 18.  Test mass potential measured using a floating probe under AC charge control, the potential is measured relative to the system’s ground-fixed enclosure, the incident UV power is 10 μW, modulation frequency is 100 Hz, duty cycle is 50%, and bias is 3.0 Vpp, the guard mass capacitance to ground is 17 pF^[34].

图 19  LISA电荷管理系统功能框图, 包括两个ULU, 其中一个作为冗余, 保证GRS中的检验质量电荷能得到有效管理, 每个ULU包括供能、控制、光输出模块, 各有12个UV LED为两个检验质量提供光源^[37]

Figure 19.  Functional block diagram of the LISA charge management system, including two ULUs, one of which serves as a redundancy to ensure effective charge management of the test masses in the GRS. Each ULU consists of power supply, control, and light output modules, with 12 UV LEDs providing light sources for the two test masses^[37].

图 20  脉冲调制示意图, UV LED与GRS中的100 kHz的注入信号同步脉冲, 通过调整100 kHz电场的方向调整紫外光的相位, 实现对检验质量电荷的调控^[37]

Figure 20.  Pulse modulation schematic, where the UV LED is synchronized with the 100 kHz injection signal in the GRS, by adjusting the direction of the 100 kHz electric field, the phase of the ultraviolet light is adjusted to regulate the charge on the test mass^[37].

图 21  不同电荷管理系统的充放电速率和测量精度^{[19,20,31–33]}

Figure 21.  Charging and discharging rates and measurement accuracy of different charge management systems^{[19,20,31–33]}.

图 22  UV micro-LED^[44]　(a)结构示意图; (b)显微镜照片

Figure 22.  UV micro-LED^[44]: (a) Schematic diagram of the structure; (b) microscopic photograph.

图 23  (a)初始电压–5 V电荷管理效果图; (b)初始电压+5 V电荷管理效果图^[53]

Figure 23.  (a) Charge management effect with initial voltage of -5 V; (b) charge management effect with initial voltage of +5 V^[53].

图 24  Micro-LED在不同温度下的I-V曲线^[54]　(a)新micro-LED; (b) 1×10⁹ ions/cm²剂量钽辐照; (c) 5×10⁹ ions/cm²剂量钽辐照

Figure 24.  I-V curves of micro-LED under different temperatures^[54]: (a) The fresh micro-LED; (b) Ta ion irradiation with fluences of 1×10⁹ ions/cm²; (c) Ta ion irradiation with fluences of 5×10⁹ ions/cm².