Chen, Jun; Fullam, Donovan P.; Yu, Shuaishuai; Böge, Olaf; Le, Phuoc Hoa; Herrmann, Hartmut; Venables, Dean S.

2019

April

Spectrochimica Acta Part A: Molecular And Biomolecular Spectroscopy

Improving the accuracy and precision of broadband optical cavity measurements

Validated

WOS: 3 ()

Normalization Broadband optical cavity Atmospheric UV/visible Aerosol Gases

218

178

183

Most extinction measurements require a stable light source to attain high precision and accuracy. Here, we present a convenient approach to normalize light source intensity in broadband optical cavity measurements. In the absence of sample extinction, we show that the in-band signal – the high finesse spectral region of the optical cavity in which sample extinction is measured with high sensitivity – is strongly correlated with the out-of-band signal. The out-of-band signal is insensitive to sample extinction and can act as a proxy for light source intensity. This normalization approach strongly suppressed in-band intensity changes in two incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) instruments with dissimilar light sources and optical cavity properties. Intensity fluctuations in an arc lamp system were suppressed by a factor of 7 to 16 and in the LED spectrometer by a factor of 10. This approach therefore improves the accuracy and precision of extinction measurements where either property is limited by the light source stability.

1386-1425

http://www.sciencedirect.com/science/article/pii/S1386142519303907

10.1016/j.saa.2019.04.015