Investigation of a CCD modulation transfer function using the speckle method at different laser wavelengths and sub-windowing options

We have experimentally investigated the MTF of a scientific grade CCD, especially considering its behavior induced by different laser wavelengths (from 470 nm to 633 nm) and varying number of total charge transfers. The MTF measurements were performed using laser speckles and utilizing the single-slit method. The MTF of the sensor was examined from zero to the Nyquist frequency. The results obtained at different wavelengths were compared. It was shown that the spectral behavior of the MTF is negligibly small; moreover the small variation is observed at the high frequency region. It was also observed that the variation of the total number of charge transfers, adjusted by size and location of the region of interest for readout pattern, is within the intrinsic error of the single-slit aperture laser speckle method.