Influence of optical element misalignment of beam spread collimation optical system on Gaussian beam propagation and transformation

Based on the generalized Huygens-Fresnel diffraction integral, taking Gaussian beam as a laser beam model, the propagation formula is deduced. When the laser beam passes through the misaligned beam spread collimation optical system. The influence of the optical element misalignment on the output beam transmitting properties was analysed and the numerical simulation was carried out based on the analysis. The result shows that the output beam becomes an off axis Gaussian beam and the beam quality becomes worse if the misalignment is greater when Gaussian beam is passing through the misaligned beam spread collimation system. With the same misalignment, long-focus optical elements have greater influence on the output beam. The adjustment of the long-focus optical elements is more important in the beam spread collimation optical systems.