Researchers at Lucent Technologies' Bell Laboratories have produced a pulsed, single-mode laser tunable in the mid-infrared range. The group achieved peak optical powers up to 60 mW at 300 K with a tuning range of about 60 nm from 100 K to 2320 K.
The work follows success in creating pulsed quantum cascade lasers at the wavelengths of 5 and 8.5 µm. While these lasers exhibited a relatively broadband (10 to 20 cm²¹) and multimode operation, they were not suitable for applications such as chemical sensing and pollution monitoring that require a tunable source with a narrow linewidth.
The new device incorporates a grating in a quantum cascade laser structure to produce the tunable, narrow-linewidth distributed feedback laser that can operate at or above room temperature.