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Mandatory Fields
Chen, Jun; Fullam, Donovan P.; Yu, Shuaishuai; Böge, Olaf; Le, Phuoc Hoa; Herrmann, Hartmut; Venables, Dean S.
Spectrochimica Acta Part A: Molecular And Biomolecular Spectroscopy
Improving the accuracy and precision of broadband optical cavity measurements
WOS: 1 ()
Optional Fields
Normalization Broadband optical cavity Atmospheric UV/visible Aerosol Gases
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.
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