High Speed Laser Beam Scanning Using an Acousto-Optical Deflector (AOD)

Abstract

The cylindrical lensing effect in high-speed laser-beam scanning using an acousto-optical deflector AOD was theoretically and experimentally investigated. As a result, both a static and a dynamic cylindrical lensing effect was found during high-speed laser-beam scans. A compensation for a cylindrical lensing effect was proven to be very important for a realization of high-speed laser-beam scanning. Examples of this compensation are an improvement in the voltage-frequency converter and the use of a cylindrical lens behind the AOD. With such compensation, the focal position deviation from the nominal focal plane could be suppressed to remain within 4 µm when the laser beam was scanned over about 300 µm on the focal plane at a 10 m/s scanning speed and a 20 kHz ramp signal frequency.