Single-shot laser beam parameter measurement system for near-infrared laser beams

We present a simple and fast technique for measuring laser beam parameters, including focus shift using Yaglass, a telecentric lens, and a camera. Our technique is based on imaging of visible fluorescence that represents caustic of the focused near-infrared laser beam. By processing a single camera frame, a large number of second-moment beam diameters are calculated simultaneously without any need for a traditional scan in the propagation direction. The ${{M}^2}$M2 values measured with this method and standard method are in excellent agreement. We extend this technique to measure the focus shift and focus spot size. This method is fast and allows the real-time monitoring of laser beam parameters simultaneously during the manufacturing process.