Response non-uniformity of beam profiling cameras at near-infrared laser wavelengths.

The response non-uniformities of laser beam profiling cameras were investigated experimentally at near-infrared laser wavelengths. A uniform-irradiance light source with near-infrared laser wavelengths, and also a visible wavelength as comparison, was constructed for testing several different commercially available beam profiling cameras. The response signals of all charge-coupled device (CCD)-type sensors showed a strong dependence on the irradiant wavelength. The pixel-to-pixel non-uniformity of CCDs at 1064 nm increased rapidly with the reduction of exposure time, whereas that of CMOS sensors was maintained independently of these parameters. The characteristics of CCDs were discussed in terms of charge leakage effect, which is a likely source of these phenomena.