Ultrashort-pulse-characterization techniques generally require instantaneously responding media. We show that this is not the case for frequency-resolved optical gating (FROG). We include, as an example, the noninstantaneous Raman response of fused silica, which can cause errors in the retrieved pulse width of as much as 8% for a 25-fs pulse in polarization-gate FROG. We present a modified pulse-retrieval algorithm that deconvolves such slow effects and use it to retrieve pulses of any width. In experiments with 45-fs pulses this algorithm achieved better convergence and yielded a shorter pulse than previous FROG algorithms.
© 1995 Optical Society of America
Original Manuscript: October 31, 1994
Published: March 1, 1995
Kenneth W. DeLong, Bern Kohler, Kent R. Wilson, Celso L. Ladera, and Rick Trebino, "Ultrashort-pulse measurement using noninstantaneous nonlinearities: Raman effects in frequency-resolved optical gating," Opt. Lett. 20, 486-488 (1995)