The invention relates to a four-wave mixing scanning type
ultrashort laser pulse time domain contrast
measuring instrument, which comprises a
beam splitter, a short-pass filter, a first planar reflecting mirror, a second planar reflecting mirror, a third planar reflecting mirror, a fourth planar reflecting mirror, an electric translation platform, a fifth plane reflecting mirror, a first cylindrical reflecting mirror, a second cylindrical reflecting mirror, a third-order nonlinear
crystal, an attenuator, a filter, a
detector and a computer, and is characterized in that
laser light is decomposed into two beams of
laser pulses with different frequencies through the
beam splitter, the two beams of
laser pulses with different frequencies shot to a third-order nonlinear material at a certain angle, two beams of four-wave mixing (Raman)
signal light beams which are different from incident laser in frequency and different in propagation direction, and the intensity of generated
signal light directly reflects the
time domain contrast of the incident laser. According to the invention, four-wave mixing
signal light which does not coincide with an
incident beam in frequency is directly acquired, the device is simpler and high in stability, and the used components and nonlinear
dielectric material are economic and cheap.