| Abstract: | In an embodiment, a dual-etalon cavity-ring-down frequency-comb
spectrometer system is described. A broad band light source is split into
two beams. One beam travels through a first etalon and a sample under
test, while the other beam travels through a second etalon, and the two
beams are recombined onto a single detector. If the free spectral ranges
("FSR") of the two etalons are not identical, the interference pattern at
the detector will consist of a series of beat frequencies. By monitoring
these beat frequencies, optical frequencies where light is absorbed may
be determined. |