High Energy Efficiency Acousto-Optic Deflector Using Two Transducers With Different Heights

In acousto-optic deflector (AOD) based on conventional array transducer structure, the phenomenon of double acoustic lobes is caused by a phase difference of $\pi $ . Only one acoustic lobe actually consumes optical power during Bragg diffraction. Therefore, the phenomenon of double acoustic lobes results in low acoustic energy utilization and limits the bandwidth of the device. In this letter, a transducer structure with two different heights is proposed, which generates a phase difference varying with the driving frequency by the difference in height between the transducers. At the center frequency, the total acoustic wavefront produced by the transducer is perpendicular to the direction of transducer arrangement, which means that it produces a stronger total acoustic intensity compared to double acoustic lobes. Therefore, it can effectively improve the utilization of acoustic energy and reduce the power consumption of AOD. Experiments have shown that the use of two AOD transducers of different heights improves diffraction efficiency by 10% and bandwidth by 20% compared to conventional phased array transducer.