We present a spectrometer for sensitive absorption measurements in liquids across broad spectral bandwidths. The spectrometer combines the unique spectral properties of incoherent supercontinuum light sources with the advantages of cavity ring-down spectroscopy, which is a self-calibrating technique. A custom-built avalanche photodiode array is used for detection, permitting the simultaneous measurement of ring-down times for up to 64 different spectral components at nanosecond temporal resolution. The minimum detectable absorption coefficient was measured to be 3.2 × 10–6 cm–1 Hz–1/2 at 527 nm. We show that the spectrometer is capable of recording spectral differences in trace levels of blood before and after hemolysis.
- biomedical diagnostics
Kiwanuka, S-S., Laurila, T. K., Frank, J. H., Esposito, A., Blomberg von der Geest, K., Pancheri, L., Stoppa, D., & Kaminski, C. F. (2012). Development of broadband cavity ring-down spectroscopy for biomedical diagnostics of liquid analytes. Analytical Chemistry, 84(13), 5489-5493. https://doi.org/10.1021/ac301108q