Nonlinear optical phase correlator for determination of the phase of subpicosecond laser pulses in the mid-IR wavelength range

The method of determination of the phase shift of the central frequency of subpicosecond laser pulse in the mid-IR wavelength range is proposed. The method is based on the generation of sum frequency radiation by two equally linearly polarized subpicosecond laser pulses of pump with a phase difference, propagating in GaSe crystals with a regular domain structure.