Collimation of high power vertical cavity surface emitting laser

Based on the principles of Gaussian beam collimation, collimation lens of different parameters were selected according to the laser beam characteristics of different high-power vertical cavity surface emitting lasers to study the different conditions of continuous and pulsed current excitation beam collimation. For a 200 μm aperture device, through the of f=3.1 mm, NA=0.68 lens, under continuous work condition, the minimum of collimated divergence angle is 1°, under the current 40 A, pulse width 60 ns, the pulse repetition rate of 1 kHz condition, the minimum collimated divergence angle is about 2°. Results also show that under the same NA conditions, the collimated divergence angle linearly decreases when focal length increases.