Lasing in optically pumped Ga(NAsP )/GaP heterostructures

We experimentally investigate the characteristics of light emission of optically excited Ga(NAsP) multiple quantum-well structures grown pseudomorphically on a GaP substrate by metal-organic vapor-phase epitaxy. The emission power as a function of excitation power shows at temperatures from 15to200K a clear threshold after excitation with short laser pulses. The emission spectra become narrow at threshold and shift to higher energies. A well defined mode structure is observed above threshold. Complementary, quasi-steady-state gain measurements using the stripe-length method yield positive modal gain values of up to 10cm−1 at room temperature, thus validating that the structures show laser action.