OPTICALLY PUMPED 4-LEVEL INFRARED-LASER BASED ON INTERSUBBAND TRANSITIONS IN MULTIPLE-QUANTUM WELLS - FEASIBILITY STUDY

The feasibility of optically pumped infrared laser based on the intersubband transitions in multiple quantum wells is studied theoretically. The criteria for the population inversion and efficient lasing operations are established. The system consisting of the superlattice with four quantum wells per period is proposed and shown to satisfy the above criteria. The relaxation processes are investigated with electron-phonon interaction being given a rigorous theoretical treatment. It is shown that in the proposed structure, optical gain in excess of 300 cm-1 can be realized under practical pumping conditions. Modification and optimization of the proposed laser are discussed.