Experimental Generation Of Bright Green Amplitude Squeezed State Of Light Via Extracavity Frequency Doubler

Squeezed light is important nonclassical light state of Quantum optical experiments. It is applied widely in quantum information, quantum communication and precise measurement etc.Optical parametric process is one of the most effective way of generating squeezed light. Many research work focused on using optical parametric down-conversion process generating squeezed light through Optical Parametric Osillator as less attention is paid on parametric up-conversion process (Second Harmonic Generation, SHG). Indeed, the setup of generating squeezed light through parametric up-conversion process is relatively simple and practical. Since in the up-conversion process, not only the foundamental mode reflect from the doubler, but also the second harmonic mode output from the doubler is squeezed so that the spectrum of squeezed light can be expanded, this process is attractive.This paper introduces the experimental generation of bright green amplitude squeezed light via extracavity frequency doubler.The semi-monolithic F-P configuration consisting of an α-cut type-Ⅱ KTP crystal and a concave mirror. The amplitude-squeezing of 3.1±0.2dB at 540 nm wavelength is obtained with the pump power of 50 mW under the conditions of the two infrared modes resonance and the green mode near resonance.