Micro-cavity surface emitting Gunn laser

Pulsed operation of a monopolar, surface emitting micro-cavity GaAs Gunn laser is demonstrated for the first time at T≥100 K. Light emission is due to the band-to-band recombination of excess carriers, generated by impact ionisation in the propagating high field domains in the Gunn device that is biased above the negative differential resistance (NDR) threshold. The current flow is longitudinally along the n-doped GaAs active layer. Therefore vertical current injection through the high resistance reflector stack that is present in conventional vertical-cavity surface emitting lasers is avoided. Furthermore, the device does not require ring contacts and the light emission occurs from the entire surface between the electrodes. Current-voltage (I-V) and light intensity against applied voltage (L-V) characteristics together with the lasing spectra are reported at T=100 K.