Photonic OH Suppression

Emission from OH molecules in the upper atmosphere is a significant contributor to the background of any astronomical image or spectra at near infrared wavelengths. This limits the depth of observations possible. The AAO, in collaboration with University of Sydney and AIP (Germany) are developing a technique to suppress OH emission using photonic technologies.

Photonic OH suppression uses fibre Bragg gratings to cancel out OH emission lines and photonic lanterns for telescope fibre coupling. These technologies were demonstrated at the Anglo-Australian Telescope via the GNOSIS and PRAXIS projects. The Eupraxia instrument is now aiming to provide demonstration on an 8-10 metre class telescope.