METHOD AND ASSEMBLY FOR OPTICAL ANALYSIS OF AN ULTRASHORT LASER PULSE

摘要

The present invention relates to an optical analysis method and assembly for analysing an ultrashort laser pulse. According to the invention, this assembly comprises a single-shot optical autocorrelator, which is made up of: a) a polarity separator (21) for angular separation of an incident laser radiation beam with fundamental optical frequency (ω) into two laser radiation beams with fundamental frequency (ω) and linear polarities which are orthogonal to one another, said two beams forming an angle α therebetween at the output of said separator, said angle α being other than zero so that said beams overlap at least partially at the output of said separator, a) a type-II non-linear crystal (22) arranged to receive said at least partially overlapping beams so as to generate, at the output of said crystal, a single laser radiation beam with harmonic frequency (2ω) propagating according to the bisector of the angle alpha formed by the two initial beams; b) at least one spectral filtering device (23) configured to selectively allow the passage of said laser radiation beam with harmonic frequency (2ω) while blocking said laser radiation beams with fundamental frequency (ω), said at least one spectral filtering device (23) being placed between said non-linear crystal (22) and a spatially resolved detection system (24) following at least one direction; c) said non-linear crystal (22), said at least one spectral filtering device (23) and said detection system (24) being arranged to detect an intesimetric single-shot autocorrelation trace of the order of two at the double optical frequency (2ω).