Gmachl’s research group is working on the development of new quantum devices, especially lasers, and their optimization for systems applications ranging from sensors to optical communications. Their special focus is currently on Quantum Cascade (QC) lasers, a novel type of semiconductor injection laser based on electronic intersubband transitions in the conduction band of a coupled quantum well heterostructure. Quantum wells are only few atomic layers thick slivers of one type of semiconductor material interleaved with another type of semiconductor, the barrier. Many performance features of the lasers, e.g. their emission wavelength in the mid- to far-infrared, power, or modulation capabilities, are designed into the device by choice of the quantum well and barriers thicknesses.
Current projects include the development of high temperature, high power, high efficiency QC lasers. Widely tunable, monolithic and external cavity, QC lasers are being developed for optical sensors in environmental, medical, and security applications. While Gmachl’s group is focused mainly on the development of the lasers, they maintain strong collaborations with many expert spectroscopists in academia, government and industrial labs, who are building sensor systems.