The scanning slit beam profiler moves a narrow slit in front of a photo-detector through the beam under analysis. Light passing through the slit onto the detector creates a photo-induced current in the detector. The slit acts as a physical attenuator in the scanning slit beam profiler, and the amplification gain on the detector can be set to avoid detector saturation for most beam profiling. A digital encoder precisely measures slit position. The photo-induced current is then plotted as a function of slit position to determine a linear profile of the beam. From this linear profile, important spatial information such as beam width, beam position, beam quality, and other characteristics are determined. This technique can accommodate a wide variety of test conditions.

Because slit scanners measure beams at high powers with little or no attenuation, they are ideal to profile beams used in material processing. Carbon dioxide (CO2) lasers are widely used in materials processing, and have a 10.6 micron wavelength that cannot be profiled with most cameras. Slit scanners, therefore, provide an convenient means of measuring high-resolution CO2 lasers with powers up to and exceeding 1000 watts.

NanoScan	High Power NanoScan
NanoScan Near-Field Profiler	Slit - Based Beam Propagation Analyzer M²