Dependence of the ultrasound-caused shifts in optical frequency and phase and the modulation of optical phase in acousto-optic interaction of turbid media

Abstract

In acousto-optic interaction, it is widely known that the frequency and phase of light are ultrasound-shifted in both transparent and turbid media, and furthermore the phase is also ultrasound-modulated in turbid media. However, it has been unclear whether there is an inherent relationship between the ultrasound-caused shifts in optical frequency and phase and the modulation of optical phase in turbid media. In the letter, we reveal that the ultrasound-caused shifts in optical frequency and phase depend on the modulation of optical phase in acousto-optic interaction of turbid media. Additionally, the intensity of frequency-shifted light is related to the modulation of optical phase. Then, with the increase of the modulation amplitude of optical phase, the phase-modulated light comprises relatively more light waves with higher frequency shifts. At last, the conclusions are confirmed by heterodyne experiments.