Abstract

Novel sub-millimeter semiconductor lasers based on the intersubband transitions between heavy-hole and light-hole subbands in germanium (see Fig. 1a) was recently constructed and investigated.¹ Population inversion takes place under heating and drift of holes in crossed electric and magnetic fields. Spectral range of emission is 70–200 μm and impulse power reaches several Watts. Device of that kind would be used for spectroscopy and for other scientific purposes, but this laser with non selective resonators has disadvantages such as wide emission line 10–15 μm and the lack of generation in some regions of mentioned spectral range. These special features restricted the possibility of practicable use of such lasers. Selective resonator described in² allows to obtain the generation as two narrow emission lines tuned with electric and magnetic fields. Resonator with moving lamellar grating described in^3,4 made possible continuous mechanical tuning from 70 to 110 μm. Probably diffraction losses did not permit to obtain long-wave generation. It is limitation of method suggested in.^3,4

© 1995 IEEE