Extraction of radiative and nonradiative rates in Sb based midwave infrared lasers using a novel approach.

We developed a technique using nonlinear correlation of photoluminescence (PL) to characterize midwave infrared lasers by extracting the density and temperature dependence of the carrier lifetime and its exact branching into radiative and nonradiative processes. This was accomplished, without time resolving the PL recovery, through mathematical optimization. We extracted this information by using a laser source that can be operated in both continuous-wave and short pulse modes. Through fitting of the PL signal and its nonlinear correlation for both laser modes of operation, the carrier lifetime as a function of density is extracted. As a proof of principle, we investigated a midinfrared Sb based laser and showed that the radiative branching ratio drops from approximately 54% at 80 K to about 3% at room temperature, resulting from an order of magnitude increase in the nonradiative rate coupled with a factor of 2 reduction in the radiative rate. We believe that this is a very generic approach and can be extended to various luminescing material systems.