Method for controlling spatial characteristics of diode lasers radiation Bulletin of the Tomsk Polytechnic University Vol. 325, № 2 : Mathematics, Physics and Mechanics
The urgency of the discussed issue is caused by necessity of designing new perspective optical devices, in particular diode lasers with the given spatial distribution of radiation directivity diagram intended for being used in acustooptics, systems of optical communication, information processing and storage, etc. The main aim of the study is to develop a new effective method of forming homogeneous or given spatial distribution of the directivity diagram of diode lasers radiation based on application of multiple-beam-reflection (beam-splitting) phenomenon in anisotropic environments. The methods used in the study: experimental research of intensity distribution for the beams leaving a single four-beam-reflecting prism and the system of such prisms; studying the features of the multiple-beam-reflection effect depending on geometry and test conditions by the example of calcite crystals with average size of birefringence (with sufficient angular resolution) and comparison of the results with the literary data; finding-out of an opportunity of applying the phenomenon for increasing the efficiency of formation of the spatial-homogeneous laser radiation, essential simplifying and expanding functionalities of transformation (correction) of cross-section radiation intensity distribution and perfection of diode laser output characteristics on this basis; analysis of polarization-amplitude characteristics of the effect, uniformity or required configuration of the directivity diagram of diode lasers radiation depending on initial beam parameters and test geometry, set of optimum conditions for increasing the efficiency of the developed method. The results: It was ascertained that the uniformity degree of a formed light profile is proportional to quantity of beams generated by the system - in the case of 16-beam geometry the greatest degree of uniformity of spatial distribution and the maximal intensity of output radiation were achieved. The geometry of a two-dimensional light matrix formed when applying multiple-beam-reflection depends both on mutual orientation of prisms, and on beams direction. The authors have proposed the variant of prism system providing the for mation of matrix light fields of various configurations. The fields can be operated effectively changing polarizing and other characteristics of the initial beam. The method proposed in comparison with analogues is characterized by simplicity in use and profitability; does not demand application of complicated intraresonator schema and adjusting processes connected with them; allows correcting effectively various irregularities of a wave surface, including those which are difficult to be removed by the other ways and caused by radiation multiple-mode. In the crystals researched the additional (transversal) shift of the reflected beams was observed. The similar shift was observed in another matters and caused the increase of efficiency of light beam transformation. It is shown, that both attenuation and intensification in the context of the method. It is of practical value.
diode laser, radiation directivity diagram, multiple-beam-reflection (beam-splitting), efficiency