Solar ultraviolet (UV) radiation is strongly absorbed in our atmosphere and triggers a variety of photo chemical reactions, strongly influencing the earth’s development. Exact knowledge of the photo chemistry of environmental trace gasses is of paramount importance to understand effects contributing to global warming and to develop strategies for its abatement. Yet, despite the enormous relevance, spectroscopic information in the UV spectral region is scarce mainly owing to the lack of intense UV laser sources.
ELFIS will surpass this limitation by transposing ultra-broadband dual frequency comb Fourier transform spectroscopy into the UV via harmonic frequency up-conversion. Linking competencies originating at the forefront of frequency comb metrology and ultrafast science will permit absorption spectroscopy in the UV spectral region with an unprecedented micro-eV resolution, unparalleled signal-to-noise ratio and record-short acquisition times. Congested absorption features of complex gas mixtures of fundamental, environmental and astrophysical importance will be recorded with a resolution at least one order of magnitude beyond state of the art.
The world’s first UV dual comb spectrometer will demonstrate its potential by exploring the Rydberg state series close to 10 eV in the air pollutant methyl iodide. Also, the new technique will permit the first complete rotationally resolved study of the Rydberg bands in the most prominent greenhouse gas carbon dioxide around 11.3 eV. Time-resolved investigations with a unique combination of ultra-high spectral and high temporal resolution will explore photo-induced dynamics in atoms and molecules involving transient effects such as level splittings, shifts and quantum beatings at a new level of detail. With ELFIS, ultrafast dynamics linked to the UV photo-induced population transfer and dissociation in methyl iodide will be tracked with an unrivalled energy state resolution (3 orders of magnitude beyond state of the art).
