A variable divergence angle laser beam shaping system with aspherical lenses

The laser beam shaping system which can convert Gaussian beam to flat-top beam has been widely applied in laser illuminating, laser materials processing and laser medical treatment, etc. For the application of laser illuminating, a laser beam shaping system with simple structure and high efficiency was developed, which used two aspherical lenses to convert the 2 mm waist diameter Gaussian beam to a flat-top beam. To achieve a long-distance illuminating for different object positions, the shaped laser beam divergence angle is required variable. Therefore, a continuous zoom lens which had the zoom ratio of 18.4:1.04 was added to the front of the aspherical lenses. By moving the axial positions of the zoom lens, the continuous change of the beam divergence angle can be achieved. With the aid of ZEMAX software, this laser beam shaping system was simulated and optimized. The simulation results showed that the beam divergence angle can be continuously changed in 1°~18°, while the laser facular area energy distribution keeping uniform of 5m, 45m and 65m illuminating distances, which can satisfy the different long-distances laser illuminating requirements.