标题： 使用同相检测提高$n$掺杂 GaAs 中自旋噪声光谱的灵敏度 显示英文标题

标题： Increased sensitivity of spin noise spectroscopy using homodyne detection in $n$-doped GaAs

摘要： 我们实现了零差探测方案，以提高自旋噪声光谱中的偏振灵敏度。 通过控制本地振荡器的激光强度，该强度围绕样品传输且不干扰被测自旋系统，我们能够提高信噪比。 测量信号强度的额外放大机会使我们能够降低入射到样品上的探测激光强度，从而接近非扰动区域。 该方案在低探测功率下信号增强超过三倍的效率已在体掺杂$n$的 GaAs 中得到演示，其中电子自旋弛豫率的降低已通过实验展示。 此外，光学相位的控制使我们能够在不改变光学装置的情况下切换法拉第旋转和椭圆度的测量。 显示英文摘要

摘要： We implement the homodyne detection scheme for an increase of the polarimetric sensitivity in spin noise spectroscopy. Controlling the laser intensity of the local oscillator, which is guided around the sample and does not perturb the measured spin system, we are able to improve the signal-to-noise ratio. The opportunity of additional amplification of the measured signal strength allows us to reduce the probe laser intensity incident onto the sample and therefore to approach the non-perturbative regime. The efficiency of this scheme with signal enhancement by more than a factor of 3 at low probe powers is demonstrated on bulk $n$-doped GaAs where the reduced electron-spin relaxation rate is shown experimentally. Additionally, the control of the optical phase provides us with the possibility to switch between the measurement of Faraday rotation and ellipticity without changes in the optical setup.