TUNABLE FAR-INFRARED SOLID-STATE LASERS BASED ON HOT HOLES IN GERMANIUM

The basic principles for achieving population inversion and stimulated emission in the far-infrared from p-Ge are discussed. In the heavy-light hole lasing mode a broad gain region is found resulting in a broad multimode, spectrum due to intracavity modes. By attaching external plates of germanium a single mode operation is realized. The obtained powers are in the W range with linewidths of almost-equal-to 0.2 cm-1. A single mode magnetically tunable coherent source is achieved with the light hole cyclotron resonance laser. With external mirrors a tuning range from 20 to 120 cm-1 with magnetic fields between 1 and 6 T is achieved. The intensity of the single mode is in the order of W, the linewidth below 0.2 cm-1.