Molecular crystal (GUHP) for narrow-band pulsed THz generation with NIR femtosecond laser

We report on the creation and investigation of a new class of crystals for nonlinear optical applications in the NIR-THz range, requiring non-critical phase matching. A narrowband two-frequency THz radiation source is demonstrated. The spectral properties of THz radiation emitted via optical nonlinear rectification in a semiorganic molecular crystal guanylurea hydrogen phosphite (GUHP) are described in relation to the crystal axis orientation.