Characterization of Ultrashort Optical Pulses by Spectral Shearing Interferometry

Ultrashort optical pulses are integral to various fields. Thus, the characterization of these pulses is crucial in understanding the results of experiments and applications using them. A diagnostic for laser systems was created to determine the shapes of ultrashort optical pulses using the principle of spectral shearing interferometry (SSI). By strongly chirping an optical pulse using a pair of parallel diffraction gratings and mixing it in a lithium triborate LiB3O5 (LBO) nonlinear crystal with two test pulse replicas delayed by 1.9 ps, sum harmonic generation of the input laser beam was achieved. The SSI interferogram was then characterized by an Ocean Optics Spectrometer using a novel “2ω method ” to determine pulse characteristics. The diagnostic was tested on the diagnostic compressor of the Multi-TeraWatt (MTW) laser system at the Laboratory for Laser Energetics, successfully determining the compressor distance for which the optical pulses were shortest. 1