Applied Physics Seminar

The quantum cascade laser has demonstrated the ability to provide gain over a very broad wavelength range. Recently, we have shown that such broadband devices, when operated in continuous wave, emit as a coherent optical comb in which the phase relation between the comb modes corresponds approximately to a FM modulated laser. By combining a Maxwell-Bloch equations and a modal decomposition, the nature of this mode-locking has been elucidated. We have also recently shown that these combs can also be produced in the THz region of the spectrum, with the gain bandwidth covering a full octave. These new comb lasers enables the fabrication of a dual comb spectrometer based on a quantum cascade laser that offers a broadband, all solid-state spectrometer with no moving parts and a ultrafast acquisition time. We demonstrate a spectrometer and its first proof-of-principle applications.