Narrowband tunable semiconductor noninjection FIR hot hole laser and its use for investigations of semiconductors

The population inversion mechanism in Ge under crossed electric and magnetic fields and far-infrared gain due to intersubband transitions of hot holes are briefly described in present work. The experimental results of gain spectral dependence are compared with calculations based on Monte Carlo and balance equations methods. The previously developed lasers of this type had the following parameters: generation wavelength region was 80-210 μm, the pulse power was about 10 W, the emission linewidth was 10-15 μm. To obtain the narrowband generation we designed two types of resonators: (1) the resonator with multilayered selective mirror, which consisted of alternating layers of Ge and Si thin plates and (2) the resonator with mode selection using the intracavity Fabry-Perot inclined interferometers. These interferometers were manufactured as plates of Si of different thickness. Two narrow generation lines have been obtained without loss of total emission power in the regions of 80-120 and 150-210 μm. The spectral width of these lines was less than 0.2 × 1/cm. The tuning is realized by the varying of the applied magnetic and electric fields. The laser design and performance are briefly described. The possibility of using this laser for the scientific investigations is shown. The cyclotron resonance of equilibrium and hot electrons in InSb and the filling of the impurity states in p-type Ge under the impurity breakdown are investigated.