The polariton laser ridge: an exception to the rule

To highlight the specific character of polariton lasers, namely the absence of reciprocity between the processes leading to gain and loss, we present here the operation of a CW polariton laser in a ridge geometry with distributed Bragg reflectors (DBRs) forming the cavities. We explore the laser threshold under optical pumping, and we investigate the effect of varying the optical pumping length. Unthinkable in the world of conventional ridge lasers, the lasing effect is reached even for a pump length of just 15% of the cavity length with only a threefold increase of the overall threshold. The experimental results are compared to numerical simulations of the dynamics of the exciton reservoir and the polariton population.