Li Wei, Yu Xudong, Zhang Jing
Opt Lett. 2015 Nov 15;40(22):5299-302. doi: 10.1364/OL.40.005299.
We present the experimental measurement of a squeezed vacuum state by means of a bichromatic local oscillator (BLO). A pair of local oscillators at ±5 MHz around the central frequency ω(0) of the fundamental field with equal power are generated by three acousto-optic modulators and phase-locked technology and used as a BLO. The squeezed vacuum light is detected by a phase-sensitive balanced-homodyne detection with a BLO. The baseband signal around ω(0) combined with a broad squeezed field can be detected with the sensitivity below the shot-noise limit, in which the baseband signal is shifted to the vicinity of 5 MHz (the half of the BLO separation). This work has important applications in quantum state measurement and quantum information.
我们展示了通过双色本地振荡器（BLO）对压缩真空态进行的实验测量。由三个声光调制器和锁相技术产生一对围绕基频ω(0)中心频率±5 MHz且功率相等的本地振荡器，并将其用作BLO。压缩真空光通过与BLO进行相敏平衡零差检测来进行探测。在低于散粒噪声极限的灵敏度下，可以检测到与宽压缩场相结合的ω(0)附近的基带信号，其中基带信号被移至5 MHz附近（BLO间隔的一半）。这项工作在量子态测量和量子信息方面具有重要应用。
