Large Amplitude Wavelength Modulation Spectroscopy for Sensitive Measurements of Broad Absorbers


This talk will present our demonstration of wavelength modulation spectroscopy (WMS) of CO2 at pressures greater than 30 atm using a fast-scanning MEMS laser. Wavelength modulation spectroscopy is a fast, sensitive technique in which one varies the laser across an absorption feature of interest while applying a high frequency (f) modulation. The resulting harmonic signals, particularly at 2f, are sensitive to the absorbance of light by the molecules, which is a function of gas conditions such as temperature, pressure, and concentration. Traditionally, the technique has been limited to lasers with small tuning ranges; thus the use of a MEMs VCSEL with a large tuning range enables the measurement of high-pressure gases and large molecules that were difficult to measure before. Finally, a simulation of WMS is presented that accommodates the unique properties of the MEMs laser and will enable the extraction of the gas properties from the measurements made.

Jun 16, 2015 3:30 PM — 4:30 PM
Bechtel Collaboratory, Discovery Learning Center
Engineering Center, University of Colorado at Boulder, Boulder, CO 80309

University of Colorado Boulder