Room temperature mid-infrared quantum cascade lasers

Operation of a quantum cascade laser at λ ~5 µm is reported up to 300 K in pulsed mode. The device uses a new design which incorporates a funnel injector and a three quantum well active region. This is the first mid-IR semiconductor laser operating at room temperature in this wavelength range. Optical powers of 15 mW at 274 K and 1.5 mW at 300 K are obtained.