Acousto-optic low-frequency shifter

This paper reports the design and performance of a practical TeO2 low-frequency shifter based on two consecutive acousto-optic interactions which eliminates spurious signals at acoustic frequencies, and reduces to very low values the second-order rediffraction of the first interaction. The design is verified experimentally, and it is seen that frequency shifts of ±12 MHz are possible with no change in the output angle of the frequency-shift order, which is in accordance with theoretical estimations.