Frequency Comb based Fourier Transform Spectroscopy

A growing list of applications of laser frequency combs includes molecular spectroscopy and trace gas sensing. Interference between two independent comb sources, whose relative coherence is forced, can in particular benefit optical diagnostics and precision spectroscopy, by taking advantage of motionless novel Fourier transform spectroscopy
(FTS). Proof-of-principle experiments of frequency comb based FTS have recently demonstrated a millionfold improvement in resolution, sensitivity and data acquisition time, when compared to the technique which has for decades assumed a position of dominance in molecular spectroscopy, Michelson based FTS.

The aim of this project is to explore the intriguing potential of frequency comb based FTS for vibrational and electronic spectroscopy. This includes the development of the technique in the mid-infrared molecular fingerprint and visible-ultraviolet regions for time-resolved
diagnostics of dynamic single-events and for hyperspectral imaging of systems of chemical, physical or biological relevance. Fourier transform interferometers based on emerging novel techniques for frequency comb generation, such as four-wave mixing of whispering gallery modes in microscopic optical resonators, will additionally lead to an extreme miniaturization of the spectrometers, which could for instance probe microscopic samples coupled to these micro-cavities. The method might also prompt other interferometry-related research fields.