High-sensitivity cavity ringdown polarimetry

Researchers from Oxford Chemistry’s Ritchie Group have developed a new variant of cavity ringdown polarimetry, described in a publication this week in The Journal of Chemical Physics. Their novel technique can be used for high-sensitivity magnetometry and chiroptical activity measurements, applicable to the development of novel Faraday rotators and the real-time characterisation of biochemical and pharmacological phenomena. The optical responses of these systems are often too small to be probed by traditional laboratory polarimeters. 

The technique employs an optical cavity of bow-tie configuration addressed by a continuous-wave laser operating at 532 nm. In order to demonstrate the effectiveness of the new methodology, the team evaluated the Verdet constants of crystalline CeF₃ and fused silica, as well as optical rotations of gas- and liquid-phase samples. Their observations were complemented by state-of-the-art calculations performed by Oxford Chemistry’s Prof. David Tew using the TURBOMOLE quantum chemistry package. 

Take a look at the full paper, featured now as an "Editor's Pick" in The Journal of Chemical Physics.

Schematic diagram of the 532 nm bowtie cavity ringdown polarimeter. Further details are in the full publication.