Submillimeter p-Ge laser using a Voigt-configured permanent magnet

A p-Ge laser at 170-200 μm wavelengths in Voigt configuration using a regular permanent magnet is reported. Results are compared with those obtained using a Faraday-configured superconducting magnet. Emission is observed over a wider range of electric-field magnitude in Voigt configuration at a given magnetic field. Time-resolved emission studies reveal unusual pulse dynamics which depend on the magnitude and duration of the applied electric field. Spectral content, Gaussian-beam profiles, and polarization are essentially independent of these temporal effects. A significant repetition-rate increase is found using copper heat sinks. An increased emission-pulse delay with increasing initial-sample temperature and the temperature independence of the emission quench time are both explained by Joule heating of the laser medium. Lasing persists above 10 K, raising the possibility of a practical p-Ge laser without need for liquid helium as a coolant