关键词: 低频压缩/
马赫-曾德尔干涉仪/
声频信号测量
English Abstract
Measurement of audio signal by using low-frequency squeezed light
Yan Zi-Hua,Sun Heng-Xin,
Cai Chun-Xiao,
Ma Long,
Liu Kui,
Gao Jiang-Rui
1.State Key Laboratory of Quantum Optics and Quantum Optics Devices, Collaborative Innovation Center of Extreme Optics, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China
Fund Project:Project supported by the National Natural Science Foundation of China (Grant Nos. 61405108, 11674205, 11604189), the Key Program of the National Natural Science Foundation of China (Grant No. 91536222), the National Key Research and Development Program of China (Grant No. 2016YFA0301404), the National High Technology Research and Development Program of China (Grant No. 2015AA8112008), and the University Science and Technology Innovation Project in Shanxi Province, China (Grant No. 2015103).Received Date:17 January 2017
Accepted Date:08 April 2017
Published Online:05 June 2017
Abstract:Measurement of audio signal plays a significant role in many applications, such as gravitational wave detection, bio-particle imaging and magnetometer. In this paper, low-frequency squeezed light is generated by a non-degenerate optical parametric amplifier. In order to avoid the effect of injected light on low-frequency squeezing, an auxiliary laser is used to lock the length of non-degenerate optical parametric amplifier and a method of locking quantum noise is employed to lock the phase between the local light and the squeezed light. By isolating the vibration noises at low-frequency and reducing back action of parasitic interference, the squeezing of (7.1±0.1) dB takes place at 19 kHz. Then the squeezed light is injected into the Mach-Zehnder interferometer to measure an audio signal which drives a piezoelectric transducer to generate a small phase variation between two arms of Mach-Zehnder interferometer. According to the low-frequency squeezing, we realize experimentally the measurement of phase signal at audio frequency which exceeds the shot-noise limit of (3.0±0.4) dB. The experiment provides technical supports for the generation of low-frequency squeezed light and the measurement of audio signal. Furthermore it can be extended to other quantum measurements, such as high-precision magnetometer and measurement of small-displacement.
Keywords: low-frequency squeezed state/
Mach-Zehnder interferometer/
measurement of audio signal
