Nonvolatile photorefractive spectral holography for time-domain storage of femtosecond pulses

Bandwidth study of volume holography in photorefractive InP:Fe for femtosecond pulse readout at 15 μm

“…This Q value is much larger than 1, indicating that the grating is a thick grating, and the angular selectivity is 2⌬ r Ϸ ⌳/d ϭ 0.03 deg. 14 At ⌳ ϭ 14 m these values become Q Ϸ 117 and 2⌬ r Ϸ 0.1 deg. Although the grating is still in the thick grating regime under the defi-nition of Q, the bandwidth of the grating diffraction is already large enough for the full spectrum of a 100-fs pulse to be reconstructed in the hologram readout.…”

“…Reading a hologram at longer wavelengths than the writing wavelength makes holograms less volatile, as was demonstrated in holographic data storage, image processing, 10 real-time holography, 13 and recently spectral holography. 14,15 A key issue for this scheme is whether the volume hologram, written by a cw laser producing a constant hologram period, will have a sufficient Bragg matching bandwidth to diffract the entire spectrum of an incident femtosecond pulse with sufficient diffraction efficiency. Our goal here is to investigate the bandwidth of femtosecond pulses diffracted from volume holograms in photorefractive InP:Fe.…”

“…The holographic recording time was 1-2 min. 14 Thin holograms such as GaAlAs/GaAs multiple quantum wells, for which the Bragg limitation is eliminated because the diffraction is in the Raman-Nath regime, have been used for femtosecond pulse shaping 17 and time-domain image edge enhancement 18 with a significantly improved response time of several microseconds with input diffraction efficiencies of 10 Ϫ3 , limited by the interaction length.…”