Transmission function of circular optical choppers for Gaussian beam distributions

Undoubtedly, optical choppers are one of the oldest and most common light modulation tools, which still have many applications in optoelectronic devices such as guidance systems, opto-mechanical mouses, and photoacoustic systems. In this study, transmission function of a chopper with circular shape apertures was studied whereas the distribution of the incident beam was considered Gaussian. A mathematical model was obtained for transmitted signals through the circular chopper. Studies were done for different ratios of apertures diameter to the beam cross section and the effect of this ratio on the profile of output pulses were studied. Finally, this model was validated by a simple optical experiment. This model can be easily extended for any laser beam profiles such as top hat beams and can be a leading method in optical devices and techniques based on the use of chopper wheels.