Hard-edge Optics-Study On The Diffraction Characteristics Of Laser Beams Limited By Apertures

In order to suppress laser oscillating mode, to realize spatial filtering and beam shaping etc., the aperture is necessary in the practical optical systems. Under the condition of paraxial approximation, the numerical simulation of the propagation of laser beams through hard-edged apertured optical systems is becoming an important problem in the hard-edge optics. Moreover, there exists Fresnel diffraction modulation in the propagation of laser beams through hard-edged apertures, and the beam intensity of distribution in the near-field region is not uniform. The Fresnel diffraction modulation should be avoided in the high-power laser systems. Therefore, many methods such as super-Gaussian aperture and serrated aperture have been proposed to reduce the Fresnel diffraction modulation. The purpose of the present dissertation is to study the simulation algorithms for hard-edge optics and the diffraction characteristics of laser beams limited by apertures with different geometries. The main results obtained are summarized as follows:1. There are usually several hard-edged apertures in the complicated optical...