Time delays and Q switching in homostructure and heterostructure injection lasers

Preliminary results are reported of a joint experimental-theoretical study of time delays and -switching effects in homostructure and heterostructure lasers. Spectral measurements of the normal lasing and -switching pulses indicate a broadening of the spectrum during the delay, with a high-energy emission during the -switched output. These experimental results are interpreted on the basis of a theoretical model involving saturable absorption of the lasing emission via states in the conduction band "tail," while the emission itself results from transitions associated with states in the parabolic part of the conduction band for temperatures above a certain critical temperature Tc.