Frequency-comb spectroscopy in the near-/mid-IR using femtosecond optical parametric oscillators (OPOs)

Femtosecond optical parametric oscillators can be operated as versatile frequency combs, with coverage from 1.0 – 5.0 µm. Two approaches are of interest to us, which allow such OPO combs to be developed for high-resolution spectroscopy. The first is in partnership with NPL's Environmental Measurements Group, with whom we are developing asynchronous OPO combs to implement broadband FTIR spectroscopy in the 2 - 4 μm wavelength band with rapid acquisition rates, high sensitivity, sub-cm^-1 resolution and no moving parts. The second approach takes a single high-repetition-rate OPO comb and uses mode filtering to achieve a near- to mid-infrared output at ~10 GHz, allowing femtosecond Fourier-transform spectroscopy developed at Heriot-Watt to be applied for full-comb spectroscopy at Hz-level acquisition rates.

In 2007 Heriot-Watt was the first group worldwide to achieve carrier-envelope-offset locking of a femtosecond OPO, and subsequently reported a nearly 3-octave spanning comb from a synchronously-pumped Ti:sapphire-pumped OPO (Sun et al, Opt. Lett. 32, 1414 (2007)). Uniquely, OPO frequency combs allow access to the important fingerprint region of many molecules with resolutions better than any conventional FTIR system. The potential of such combs remains unrealised for spectroscopy, therefore motivating the development of OPO combs for this purpose. Working with NPL, we aim to develop a comb-based alternative to environmental DIAL gas sensing, which unlike DIAL will provide simultaneous sensing of multiple gas species.

Further background information is available in the form of journal downloads from the Publications area of Heriot-Watt's Ultrafast Optics Group website.

The vacancy must be filled before 1 November 2012. It is based in Heriot-Watt's Ultrafast Optics Group, working under the supervision of Prof. Derryck Reid. The position is fully funded and open to exceptional candidates of any nationality.

Enquiries may be addressed to Prof. Derryck T. Reid at [Email Address Removed]