A novel measurement approach for near-edge x-ray absorption fine structure: continuous 2$π$ angular rotation of linear polarization

Tracking capacitance of liquid crystal devices to improve polarization rotation accuracy

We report a capacitance tracking method for achieving arbitrary polarization rotation from nematic liquid crystals. By locking to the unique capacitance associated with the molecular orientation, any polarization rotation can be achieved with improved accuracy over a wide temperature range. A modified relaxation oscillator circuit that can simultaneously determine the capacitance and drive the rotator is presented.

超导单光子探测器偏振相关光吸收的阻抗模型

Impedance model for the polarization-dependent optical absorption of superconducting single-photon detectors

测量了NbN超导单光子探测器在488 ~ 1550 nm波长范围内的单光子探测效率与入射光偏振态的关系。偏振对比度从488 nm处的~5%变化到1550 nm处的~30%，与数值计算吻合良好。我们使用一个光阻抗模型来描述平行于探测器导线的偏振吸收。对于有损耗的NbN薄膜，通过保持层厚和填充因子的乘积不变，可以保持吸收恒定。因此，我们发现，最大可能的吸收是独立的填充因子。通过衬底照射探测器，Si或GaAs上的探测器可以达到约70%的吸收效率，而不需要光学腔。