Characterizations Of Combination, Propagation And Illumination Of Multibeam Lasers

The characterizations of combination, propagation and illumination ofmuItibeam lasers are mainly studied in this dissertation, which are significant for thepractical application of laser illumination technology. The main work of thisdissertation is sumn1arized as follows.l. The proceedings of laser illumination and laser diode array are presented. Acomprehensive review of the basic analytical methods for the beam transformation issummarized, Which includes the matrix optics, general diffraction integral andWigner distribution function methods.2. By use of the model of 1D and 2D beam combinations of off axisHermite-Gaussian beams, beams emitted from laser diode bar and stacked array aresimulated and studied in terms of the beam quality, astigmatism and symmetrization.The correspondent closed expressions of M2 factor and intrinsic astigmatism a arederived. The beam widths of the beam emitted from a laser diode array along x, ydirections are measured.3. The propagation and transfOrm properties and beam qualities of combinationof general astigmatism Gaussian beams, Gaussian Schel-model beams areinvestigated, respectively. In addition, the polarization characterization ofconlbination of polarized Gaussian beams is investigated.4. The propagation characterization of multi-Gaussian'beams (MGB) is studiedand compared with that of super-Gaussian beams (SGB). It is fOund that theflat-topped MGB and SGB have similar propagation property, if their generalFresneI numbers are equal. Based on the definition of second-order n1oments, t11eclosed expressions of beam width, far field divergence, M factor and kurtosisl llparameter K are derived by use of Wigner distribution function.5. The concept of multi-PGSM is proposed firstly, of which the multi-GSM and multi-Gaussian beams can be regarded as special cases. Its propagation and polarization property is investigated. The closed expressions of beam width, far field divergence, M2 factor, K parameter and degree of polarization are also derived.6. The irradiance fluctuation of multibeam laser illuminating target in air is studied in experiments and simulated numerically in various cases of optical turbulence. The effects of coherence properties of laser source on the irradiance fluctuation are also discussed.The above results are of great significance for the use of multibeam lasers as illumination source and the description of beam emitted from laser diode array.