Recent Developments in Experimental Techniques for Measuring Two Pulses Simultaneously

Abstract

As many high-intensity ultrafast-optical measurements involve more than one pulse-typically one to excite a medium under study and another to probe it-a technique for measuring two pulses simultaneously is highly desirable. In two decades, two-pulse measurement techniques have advanced from ambiguity-laden to a recently developed technique that can measure a pulse pair with arbitrary central wavelengths, complexities and bandwidths. Here, we review recent efforts to simultaneously measure two ultrashort laser pulses using a single device.

Unambiguous ultrashort pulse reconstruction from double spectrograms alone

“…where j 1 ˜and j 2 ˜are the spectral phase functions of the pulses. Next, equation (21) can be rearranged to give…”

“…As X, E 1 ˜and E 2 ˜are unknown, the final step requires an iterative method for factorizing equation (21). Where (30), ( 22), ( 23), (26), and (27) represent the individual parts of the iterative factorization process, this is summarized in figure 5.…”

Ultrashort pulses autocorrelator based on supercontinuum generation in highly nonlinear fibres

“…Thus, the most common techniques are intensity and interferometric autocorrelation (IAC) [6,7], frequency-resolved optical gating (FROG) [8] and similar variations like spectral phase interferometry for direct electric-field reconstruction [9]. All these techniques require the use of an optical autocorrelator and second harmonic generation (SHG) in a nonlinear crystal [10]. Consequently, the final implementation, based on bulk optics, results usually in being uncompact, difficult to align and sensitive to the environment.…”

Femtosecond-Laser-Pulse Characterization and Optimization for CARS Microscopy

“…[ 22 ] It is worth mentioning that the issue here of interest, i.e. the characterization of two unknown laser pulses–rather than just one,–was also extensively addressed in the past years [ 23 ] with specific variations of the FROG scheme, in particular with the so-called Blind FROG [ 24 ] and the more robust Double Blind FROG (DBFROG) [ 25 ]. In DBFROG, each of the two pulses is used as an optical gate for the other and two different spectra of the chosen non-linear signal (e.g.…”