Study of beam shaped of large-aperture top-emitting laser device

Abstract The output beam of the large-aperture top emitting laser is a kind of annular beam, the beam quality of which is poor and the spot energy distribution is not uniform. This characteristic of large-aperture top-emitting laser restricts its application in many fields. In order to improve the annular light profile to flat-top beam, a beam shaped DOE designed by modified G–S algorithm which based geometric mapping is applied on the surface of the output aperture. The simulation results show that the designed diffractive optical elements have good shaping effect and high light energy utilization. The output characteristics of the devices with and without DOE are tested in the lab. It found that the beam of the device with DOE appears more uniform than the device without DOE and as the injected current increased the light intensity of the center maintain a good uniformity.