Katashi Masumoto

Mid-infrared (5–12-µm) and limited (5.5–8.5-µm) single-knob tuning generated by difference-frequency mixing in single-crystal AgGaS 2

We describe tunable 5-12-microm mid-infrared generation in single-crystal silver gallium sulfide (AgGaS(2)), from nonlinear optical difference-frequency generation. Signal and idler waves obtained from a Nd:YAG laser-pumped LiNbO(3) optical parametric oscillator (OPO) were mixed in AgGaS(2) crystal to yield difference-frequency waves. For the efficient generation of difference frequency, an unstable resonator was employed as the OPO to reduce output beam divergence. A maximum difference-frequency power of 95 microJ/pulse was obtained near 7.5 microm for a 1-cm-long AgGaS(2) crystal. Spectral noncritical phase matching within a specific tuning range was also investigated that permitted limited single-knob tuning (5.5-8.5 microm) of the difference-frequency generator.

Cyclotron resonance of photoexcited holes in high quality ZnSe

Heavy hole cyclotron resonance has been observed in ZnSe single crystals at 35 GHz using time-resolved cyclotron-resonance equipment. Holes have been created by a xenon flash lamp. The heavy hole resonance is almost isotropic and corresponds to a polaron effective mass of mhp*=(1.04±0.04)m0. In addition, the polaron coupling constant αh for heavy hole is derived to be αh=0.983.