Whispering gallery mode HgCdTe laser operating near 4 μm under Peltier cooling

Due to their widely tunable bandgap, HgCdTe heterostructures with quantum wells are a promising material system for semiconductor lasers in the entire mid-infrared range. Recently, Auger-suppressed structures allowed interband stimulated emission (SE) in the atmospheric transparency window 3–5 μm well above 200 K, while previously it was limited to temperatures below 175 K. In contrast to earlier works focused on ridge or vertical emitting HgCdTe lasers, here we demonstrate a whispering gallery mode microdisk (d = 50 μm) laser operating under optical pumping at ∼4 μm in the temperature range attainable by the thermoelectric cooling. Above 200 K, the emission spectrum consists of multiple 0.37-meV-wide peaks associated with the modes of the disk resonator. Laser generation is achieved up to 230 K, which is 40 K lower than the quenching temperature of SE in the unprocessed macroscopic sample. We associate the difference with the optical losses introduced by the inclined walls of the disk.