Electrically pumped mid-infrared random lasers

Electrically pumped random lasers, operating in the mid-infrared regime at λ ≈ 10 μm, are realized for the first time. Randomly distributed air holes are patterned onto a quantum cascade wafer emitting in the transverse-magnetic (TM) polarization. The advantage of employing TM polarized gain medium is that TM modes are more effectively confined in the gain region, and thus improve lasing efficiency and vertical confinement compared to TE modes.