Determination of the characteristics of ultrashort laser pulses in a three-channel autocorrelator with switches based on the quadratic electro-optic effect

An analysis is made of the operation of a three-channel correlator used in the determination of the time dependences of the intensities of single ultrashort laser pulses of arbitrary structure. The control channels of the correlator have switches based on the quadratic electrooptic effect. The fifth-order correlation function I⁽⁵⁾(τ₁, τ₂, τ₃, τ₄) with τ₁ = τ₂, τ₃ = τ₄ is recorded at the correlator exit. The proposed and analysed procedure for the processing of the recorded information makes it possible to determine the structure of an optical signal in the form I(t). The procedure is based on the conversion of the signal to the spectral representation and the use of the real part as well as of the derivative (with respect to the frequency ω₃) of the imaginary part of I⁽⁵⁾(ω₁, ω₃) when ω₃ = –ω₁.