T. Laurila, I.S. Burns, J. Hult, J.H. Miller and C.F. Kaminski, "A calibration method for broad bandwidth cavity enhanced absorption spectroscopy performed with supercontinuum radiation", Applied Physics B, Vol. 102(2), 271-278, (2011), DOI:10.1007/s00340-010-4044-4 |
An efﬁcient calibration method has been developed for broad-bandwidth cavity enhanced absorption spectroscopy. The calibration is performed using phase shift cavity ring-down spectroscopy, which is conveniently implemented through use of an acousto-optic tunable ﬁlter (AOTF). The AOTF permits a narrowband portion of the SC spectrum to be scanned over the full high-reﬂectivity bandwidth of the cavity mirrors. After calibration the AOTF is switched off and broad-bandwidth CEAS can be performed with the same light source without any loss of alignment to the set-up. We demonstrate the merits of the method by probing transitions of oxygen molecules O2 and collisional pairs of oxygen molecules (O2) 2 in the visible spectral range.