Spatial-temporal wave mixing for space-time conversion

A nonlinear optical processor is developed which is capable of true real-time conversion of spatial-domain images to ultrafast time domain optical waveforms. It is based on four wave mixing between the spatially Fourier transformed quasi-monochromatic images and the optical waves of spectrally decomposed ultrashort pulses. A cascaded second-order nonlinearity arrangement in a β-barium borate crystal with type II phase matching is utilized to achieve efficient wave mixing at a femtosecond rate.