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ulti-channel acousto-optic modulator is an acousto-optical device with multiple transducers modulated in parallel, which main applications are in microfabrication and direct writing lithography. Crosstalk has been a key problem in multi-channel acousto-optical devices due to the proximity of the channels and the diffraction of the acoustic waves. Acoustic crosstalk is caused by a certain dispersion angle of the sound beam in the process of spatial propagation, resulting in the sound field of the acousto-optical action medium in a certain propagation distance overlap. Ultrasonic transducer is an important element of the sound energy emission, which generates sound waves through the inverse piezoelectric effect. The shape of the electrodes on the transducer controls the area where the piezoelectric crystal vibrates, further affecting the distribution of the sound field. Therefore, the shape of the electrodes can be changed to improve the collimation of the acoustic beam and thus effectively reduce the acoustic crosstalk problem between channels. Rectangular electrodes are used by most conventional multi-channel acousto-optic modulator. The rectangular electrodes have more acoustic field side lobes, which can cause acoustic crosstalk between sensors and thus affect the quality of the diffracted beam. In this paper, crossed trapezoid array electrodes shape is proposed, for improving the crosstalk problem of multi-channel acousto-optical devices. From the spectral analysis, the crossed trapezoid array electrodes can effectively suppress the side lobes of the acoustic field and improve the collimation of the beam, thus reducing the acoustic beam crosstalk between channels. Simulation and experiments show that multi-channel acousto- optic modulator with crossed trapezoid array electrodes can effectively solve the acoustic beam crosstalk problem between channels and enhance the performance of multi-channel acousto-optic devices.
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