Ultrashort laser pulse splitting upon resonant reflection on a mirror-based waveguide grating

Abstract : A resonant waveguide grating based on a high reflectivity mirror causes a 2pi phaseshift of adjustable slope in the spectrum of an ultrashort light pulse, giving rise to a controllable, lossless temporal pulse splitting. This monolithic phase shifter can simply be placed on the path of the beam as a mirror. A functional element was designed and fabricated. Temporal splitting of a femtosecond laser pulse is experimentally demonstrated. The possibility of obtaining variable delay between subpulses is theoretically discussed.