Scientists at the Naval Research Laboratory's Optical Science Div. have developed several types of semiconductor lasers that emit light in the mid-infrared.
One of the secrets behind the design is a new capability called "wavefunction engineering" that enables the team to design complex layered quantum well structures. The structures are based on the antimonide family of III-V semiconductors and are grown by molecular beam epitaxy. One laser incorporates a gallium indium antimonide hole quantum well, sandwiched between two indium arsenide electron quantum wells and aluminum antimonide quantum barriers. The researchers say the new IR laser (emitting between 3 and 5 µm) could prove useful for chemical sensing, protection against heat-seeking missiles, laser surgery and laser radar.