Research On Transmission Propagation Of Laser Beams Through A Optical System

Based on the work at home and abroad, some studies have been done in this dissertation. They are summarized as follows:By using the vectorial Rayleigh-Sommerfeld integrals, the propagation expressions in free space for Hermite-Gaussian, Laguerre-Gaussian, and Hermite-LaguerreGaussian beams are derived and the corresponding far-field results are also presented.It is shown that the field of nonparaxial beams is vectorial in nature, so both the longitudinal and the transversal componets of the field should be taken into account. The nonparaxiality and vectoriality of the beams increases with the increasing parameter f. Comparison of the results of different approaches shows that the method of using the vectorial Rayleigh-Sommerfeld integrals possesses obvious advantages over the perturbation series method. The new methods developed in this dissertation are relatively simple and efficient in finding the vectorial analytical expressions for the nonparaxial beams, which are more tractable in analyzing the propagation properties of the nonparaxial beams and the divergence of perturbation series solution is avoided.Using the complex expansion approach the propagation of Hermite-LaguerreGaussian(HLG) through a ABCD optical system with hard rectangular aperture is studied. The analytical expressions for the propagation of HLG beams of any orders through the ABCD optical system with hard rectangular aperture are derived, with the analytical expressions on the axis and unapertured being given as special cases.In order to study properties of propagation of hollow beams through a paraxial optical ABCD system with a hard-edged circle aperture and a lens, the expressions for the propagation of hollow Gaussian beams through such a system are derived based on the Collins diffraction integral. The effects of an aperture, a lens and an aperture-lens system on the properties of propagation of hollow Gaussian beams are studied and illustrated with numerical examples, which shows that both aperture and lens can shift the field of hollow Gaussian beams towards the source plane. It is also found that hollowness of the beam will be destroyed by the aperture, but not by the lens.