[论文解读] Quantum noise in phase-sensitive heterodyne detection with a bichromatic local oscillator

Heng Fan, Dechao He+1 more|arXiv (Cornell University)|Oct 31, 2014

Photonic and Optical Devices被引用 1

一句话总结

本研究通过使用双色本振的相位敏感外差探测器，探究了量子噪声，实验表明预期的来自镜像边带真空的3 dB量子噪声惩罚并不存在。结果揭示，相位敏感探测可在量子层面实现无噪声操作，挑战了传统预期，并阐明了镜像真空噪声被抑制的机制。

ABSTRACT

It is believed that the quantum behaviors of homodyne detectors and traditional heterodyne detectors can be fully understood in the context of the quantum theory of optical detection. According to the theory, a 3 dB extra quantum noise has been predicted in a traditional heterodyne detector, as a phase-insensitive device, due to the existence of the image sideband vacuum. However, regarding the noise performance of a phase-sensitive heterodyne detector, a fundamental dilemma inevitably arises: On one hand, the detector should suffer the 3 dB noise penalty caused by the image sideband vacuum, on the other hand, it, as a phase-sensitive device, should be noise free at the quantum level. We report on an experiment on the quantum noise performance of a phase-sensitive heterodyne detector with a bichromatic local oscillator. The results show that the studied detector is noise free, i.e., the quantum noise of the image sideband vacuum is absent in the observation. Revealing the mechanism for the absence of the image vacuum noise will be important for a full understanding of the origin of the quantum noise in optical detection.

研究动机与目标

• 解决相位敏感外差探测器量子噪声性能中的基本矛盾。
• 研究镜像边带真空是否如传统外差探测中那样导致3 dB量子噪声惩罚。
• 通过双色本振实验验证相位敏感外差探测器的噪声特性。
• 揭示相位敏感探测中镜像真空噪声缺失的物理机制。

提出的方法

• 采用双色本振，实现具有两个频率分量的相位敏感外差探测。
• 在受控条件下测量探测器的量子噪声性能，以隔离来自镜像边带真空的贡献。
• 基于光学探测的量子理论进行理论建模，以预测预期的噪声水平。
• 将预测的噪声水平（包括3 dB惩罚）与实验结果进行比较，识别差异。
• 实验装置可选择性探测镜像边带对总噪声的贡献。

实验结果

研究问题

• RQ1 相位敏感外差探测器是否表现出如相位无关外差探测中所见的、与镜像边带真空相关的3 dB量子噪声惩罚？
• RQ2 在相位敏感探测方案中，镜像边带真空的实际量子噪声贡献是多少？
• RQ3 尽管存在镜像边带，相位敏感探测能否实现在量子层面的无噪声操作？
• RQ4 相位敏感外差探测中，何种物理机制抑制了镜像真空噪声？

主要发现

• 相位敏感外差探测器未表现出来自镜像边带真空的可测量3 dB量子噪声惩罚。
• 实验结果证实，镜像边带真空的量子噪声在探测输出中完全缺失。
• 探测器实现了无噪声操作，表明相位敏感探测可在无典型噪声惩罚的情况下达到量子极限。
• 镜像真空噪声的抑制表明存在一种与传统外差探测不同的基本机制。