Kiwanuka SS, Laurila TK, Frank JH, Esposito A, Blomberg von der Geest K, Pancheri L, Stoppa D, Kaminski CF, "Development of broadband cavity ring-down spectroscopy for biomedical diagnostics of liquid analytes" Analytical Chemistry, 84 (13), pp 5489–5493 (2012) DOI:10.1021/ac301108q |
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.