Feature

Ultrashort Pulse Autocorrelator

Jinendra K. Ranka and Alexander L. Gaeta, School of Applied and Engineering Physics, Cornell Univ., and Andrius Baltuŝka-Maxim S. Pshenichnikov, and Douwe A. Wiersma, Ultrafast Laser and Spectroscopy Laboratory, Univ. of Groningen, Groningen, The Netherlands.

The standard technique for characterizing an optical pulse in the range of a few picoseconds to sub-10-fsec in duration is to measure its intensity autocorrelation. The measurement of such an autocorrelation requires a material whose nonlinear optical response scales uniformly with the square of the incident pulse intensity over a bandwidth greater than that of the pulse. The most common approach is to detect the amount of second-harmonic light generated by a χ(2) crystal in a Michelson-type autocorrelator as one arm is scanned.