Amplified reflection via degenerate four-wave mixing in a laser induced free carrier plasma in germanium
The first observation of amplified reflection at CO2 laser wavelengths via degenerate four-wave mixing in an optically induced free-carrier plasma in germanium is presented. Reflectivities of over 100% are reported in both n-type and p-type Ge. A model is presented which predicts both the magnitude and the I(2) intensity dependence of the reflectivity from the free carrier plasma density. This density is determined experimentally by time-resolving the incident and transmitted signals obtained above the plasma formation threshold and deducing the free carrier density via a detailed model which relates this quantity to the instantaneous, intensity-dependent transmission.
Presented at the Intern. Conf. on Excited States and Multiresonance Nonlinear Opt. Process in Solids
- Pub Date:
- Beam Plasma Amplifiers;
- Laser Plasmas;
- Optical Reflection;
- Plasma Physics