Optimization of Diode LaserQ-Switching Using Optical Choppers for Improved Rhodamine B Degradation

Abstract

Choppers are optomechatronic instruments employed to modulate laser light by generating pulses with unique profiles. This study investigates six chopper designs with rotating wheels, focusing on mechanical active Q-switching modulation to convert continuous wave diode lasers into Q-switching lasers. Four of the designs feature single and dual frequencies, while the remaining two are harmonic frequency optical chopper blades. The research examines key pulse characteristics, such as duration, which range from 9.38 ns to 1.034 μs for single- and dual-frequency choppers. The maximum peak power recorded was 68.98 kW for harmonic oscillation choppers, while the minimum was 1.94 kW for single- and dual-frequency choppers. The influence of chopper motor speed on laser properties is examined. Optimized chopper-laser pulses generate greater peak power and reactive species, leading to accelerated degradation of Rhodamine B, whereas continuous lasers provide slower, less intense energy for degradation.