A ROUTE FROM THE NEGATIVE-EFFECTIVE-MASS GENERATORS TO THE PHONON-DIFFERENCE FIR LASERS

Solid-state sources covering the wave number range from 5 to 120 cm(-1) are considered. Experimental data on the negative effective masses, the inverted cyclotron resonance transitions, as well as the light-to-heavy hole band transition inversion are compared with existing theoretical models. On the basis of this comparison, the phonon-difference process inversion is proposed as a new mechanism of stimulated FIR radiation. Contrary to the previous models which require complicated carrier-energy band structures, like that in p-type Ge, the two-photon difference radiation is expected to act both in p- and n-type materials. Magnetic fields and cooling down to liquid helium temperatures are not necessary for its operation. Crystalline Si, Ge, A(3)B(5), A(2)B(6) and other semiconductor compounds are candidates for creating lasers on phonons.