Second quantized state lasing of a current pumped single quantum well laser

Newly observed features of quantum well lasers are presented and explained with the aid of a simple model. These involve lasing with gain contributions not only from the fundamental (n=1) state, but simultaneously from the second quantized (n=2) state as well. Experimental data for current pumped GaAlAs/GaAs single quantum well lasers are presented. Very high resonator losses (≳100 cm−1) force the lasers to augment their gain with major contributions from the second quantized state. The main signature of n=2 lasing, a sudden and large increase in the lasing photon energy, is observed and explained by the theory.