Intensity Distribution Investigation And Beam Shaping About The High-power Laser Diode Array

Due to their relative cheapness,small bulk, light weight, long service time, high transferring efficiency and so on, high power laser diode array(LDA) are wide commercial available. Such as they are becoming increasingly attractive as pump sources for high power solid-state lasers. Unfortunately, because of the highly elliptical output beam ( such as: lμm x 10mm), they cannot readily be focused into small,circular spots, which are suitable for efficient pump sources of solid-state lasers, LDA's applications have been limited. To date,many of the pump schemes which have been employed with diode arrays have either produced a large focused beam,or have employed relatively complex designs .To overcome the shortage, above all ,it is especial important to make certain the nature distribution of the laser beam emitting from high power laser diode array(LDA),then, on the basis of it ,a high-efficient and relative-simple laser beam shaper should be provided. So this paper include following two points :one is to construct a new theoretical model about intensity distribution of LDA beam and it's validity has been attested by test , Meanwhile the first-hand data of LDA beam character have been attained; the other is to provide a shaping scheme which consist of a collimating module and a compression module ,we have practice it from fabricate ,fixing to experimentation.Our intensity distribution test system mainly includes the following five parts: photovoltaic sensor(with fibre),electro-motion flat,laser-power meter,MCC 1608fs data acquisition board,a computer has been installed labview8.5.With the help of it we attain the three dimensional beam profile displays of LDA (include: two-dimension and one-dimension if necessarily),at the same time, a tremendous amount of information data has been saved in a txt file. Finally by analyzing these data we can obtain the parameters about the laser beam such as :beam size ,relative beam power ,relative peak power, divergence angle,M2 factor and so on.Our beam-shaping system which consist of two parts. The first part of it is a collimating module with micro-hyperboloid cylinder—cylinder lens that will considerably decrease the diverging angle of laser diode in fast axis and slow axis to several mrad. The second part of it is a compression module with ellipse-plane lens and plane-cylinder lens which can compress the beam size from 10mm to less than 1 mm in the slow axis . In terms of theoretical analysis about beam shaping system, according to the basic principle of light-ray propagation, through calculations and deducing,its collimating characteristic, intensity distribution and transfer efficiency of light energy are analytically showed and discussed,and its far-field divergence angle is computed with Fraunhofer diffraction integral formula, and compared with the experimentation result.