亚散粒噪声亚赫兹激光干涉测量研究

Sub-Shot-Noise Sub-Hertz Laser-Interferometric Measurement

由于具有超高灵敏度,激光干涉测量被广泛应用于基础科学研究和技术开发领域。然而,低频经典噪声(小于1 Hz)占据干涉仪系统噪声贡献的主导地位,实现亚散粒噪声极限的低频激光干涉测量仍然面临巨大挑战。以亚赫兹低频物理信号为探测目标,采用激光偏振自由度作为干涉仪内部光能量分离通道的方法,解决激光干涉信号读出方案中本振光难以获取的关键难题;使用双频工作激光将低频位移信号在系统输出端转换为高频交流光电信号,自然地避开1 Hz频段电子学噪声的技术难题等,为量子噪声极限超低频率激光干涉、干涉信号的读出方法等提供重要的理论指导和实验支持,有望为地面引力波天线的升级改造提供具有参考价值的路径和方案。

Laser-interferometric measurements,possessing the ultra-high sensitivity,have been widely applied to fundamental scientific research and practical technological developments.However,low-frequency classic noise(less than 1 Hz)dominates exclusively in the interferometer system and measurement of sub-Hertz physical signals beyond the shot noise limit is still facing great challenges.Using the degree of freedom of laser polarization as the separation channel of light energy in the interferometer and the sub-Hertz low-frequency physical signal as the detection target,the key problem of difficult acquisition of local oscillator light in the readout scheme of the laser interference signal is solved.A dual-frequency working laser is used to convert the low-frequency displacement signal into high-frequency AC photoelectric signal at the system output to naturally avoid the technical problems of 1-Hz band electronic noise,thereby providing important theoretical guidance and experimental support for quantum noise limit ultra-low-frequency laser interference and interference signal readout method.It is expected to provide a reference path and scheme for upgrading ground gravitational wave antenna.