Frequency-doubling of femtosecond pulses in walk-off compensated N-(4-nitrophenyl)-L-prolinol

Summary form only given. N-(4-nitrophenyl)-L-prolinol (NPP) is an organic molecular crystal developped by molecular engineering, that exhibits one of the highest phase-matchable second-order susceptibilities reported so far in the near-infrared spectral range (d/sub eff//spl ap/56 pm/V). However, the large spatial and temporal walk-off existing in NPP can limit severely the usefulness of the material away from the noncritical phase-matching (ncpm) wavelength and for shorter pulses. Here we show that subpicosecond pulses can be efficiently frequency-doubled and mixed in NPP with moderate pump intensities, by employing tilted pulse techniques. These techniques make use of the large Poynting vector walk-off exhibited by NPP crystals outside the ncpm. Such techniques are based on the diffraction of the input pump wave by a grating so that each spectral component is dispersed in a different direction, thus the resulting signal is a tilted pulse.