TRANSFER-FUNCTION OF SPATIAL-FREQUENCIES IN PARAMETRIC IMAGE AMPLIFICATION - EXPERIMENTAL-ANALYSIS AND APPLICATION TO PICOSECOND SPATIAL-FILTERING

We recently performed the parametric amplification of a monochromatic near-infrared image, in a KTP crystal with a resolution of 60 X 80 points and a gain of 15 dB. In this paper, we directly measure the transfer function of spatial frequencies by recording the image Fourier plane. This analysis confirms the link between the phase-matching conditions and the resolution. Moreover, parametric amplification can act either as a low pass filter or as a band-pass filter, depending of the orientation of the crystal. Consequently, basic image processing operation can be performed.