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 ω0 of the fundamental field with equal power are generated by three acousto-optic modulators and phase-locked, which are used as a BLO. The squeezed vacuum light are detected by a phase-sensitive balanced-homodyne detection with a BLO. The baseband signal around ω0 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 the important applications in quantum state measurement and quantum information
@article{arxiv.1510.09062,
title = {Measurement of the squeezed vacuum state by a bichromatic local oscillator},
author = {Wei Li and Xudong Yu and Jing Zhang},
journal= {arXiv preprint arXiv:1510.09062},
year = {2023}
}