Analysis of the form of ultrashort pulses by spectral nonlinear interferometry

A new method for recording the phase structure of ultrashort optical pulses is proposed that makes no use of a reference pulse. Using three-wave interactions in a nonlinear optical medium, a wave of spectral decomposition of an ultrashort pulse is transformed into a monochromatic wave. The spatial phase structure of this wave contains information on the phase structure of the pulse spectrum and on the pulse form. This structure is analyzed by shearing interferometry.