Solid state electrically injected exciton-polariton laser
Pallab Bhattacharya, Bo Xiao, Ayan Das, Sishir Bhowmick, and Junseok Heo
Accepted
Inversionless ultra-low threshold coherent emission, or polariton lasing, can be obtained by spontaneous radiative recombination from a degenerate polariton condensate with non-resonant excitation. Such excitation has, hitherto, been provided by an optical source. Coherent emission from a GaAs-based quantum well microcavity diode with electrical injection is observed here. This is achieved by a combination of modulation doping of the wells, to invoke polariton- electron scattering, and an applied magnetic field in the Faraday geometry to enhance the exciton-polariton saturation density. These measures help to overcome the relaxation bottleneck and to form a macroscopic and degenerate condensate as evidenced by angle-resolved luminescence, light-current characteristics, spatial coherence and output polarization. The experiments were performed at 30 K with an applied field of 7 Tesla.