Current research:
In quantum well semiconductor lasers, the diffraction effect caused by quantum size makes the beam quality of semiconductor lasers very poor. The divergence angle of the vertical junction plane of this structure is limited to about 40, which makes the beam shaping system more complicated and limits the direct application of semiconductor lasers. In order to solve this problem, the requirement of reducing the divergence angle of vertical joint surface is put forward. The technical development and application of semiconductor lasers with small divergence angle are summarized. Theoretical simulation and experimental verification of the small divergence angle mode extended waveguide structure are carried out, and the optimized structure is obtained. The epitaxial wafer is grown by MOCVD epitaxial technology to make a high peak power pulse laser. A semiconductor laser with fast axis divergence angle less than 25 and peak power greater than 80W is obtained, which has achieved good results in laser fuze application.
Measurement of plane divergence angle;
There are many methods to measure the divergence angle of Gaussian beams, but it is generally difficult to measure a very small divergence angle, such as the divergence angle of 20μrad. In order to measure such a small angle, an inverted laser collimating telescope is used here, and the divergence angle to be measured is amplified first, and then measured. At the same time, the influence of the positioning error of the inverted laser collimating telescope on the magnification of the divergence angle is analyzed, and the feasibility of measuring the divergence angle of the tiny Gaussian beam with the inverted laser collimating telescope is obtained.