  Time-resolved spectroscopic temperature measurements of a sealed carbon
dioxide sample cell were realized with an optical frequency comb combined with
a two-dimensional dispersive spectrometer. A supercontinuum laser source based
on an erbium fiber mode-locked laser was employed to generate coherent light
around 2000 nm (5000 cm-1). The laser was passed through a 12-cm long cell
containing CO2, and the transmitted light was analyzed in a virtually imaged
phased array- (VIPA-) based spectrometer. Broadband spectra spanning more than
100 cm-1 with a spectral resolution of roughly 0.075 cm-1 (2.2 GHz) were
acquired with an integration period of 2 ms. The temperature of the CO2 sample
was deduced from fitting a modeled spectrum to the line intensities of the
experimentally acquired spectrum. Temperature dynamics on the time scale of
milliseconds were observed with a temperature resolution of 2.6 K. The
spectroscopically-deduced temperatures agreed with temperatures of the sample
cell measured with a thermistor. Potential applications of this technique
include quantitative measurement of carbon dioxide concentration and
temperature dynamics in gas-phase chemical reactions (e.g., combustion), and
plasma diagnostics.
