Computational Modeling of a ROTADE Sensor

Noemi Zakarias, Susan Minkoff, and John Zweck,
Department of Mathematics and Statistics

The resonant optothermoacoustic detection (ROTADE) method relies on the theory of optothermal spectroscopy and the mechanical and piezoelectric properties of a quartz tuning fork. ROTADE sensors enable detection of trace gases for air quality monitoring, industrial process control, and medical diagnostics. To detect a trace gas, modulated laser radiation is directed between the tines of a tuning fork. The laser source transfers energy to the trace gas molecules, these diffuse in space and come into contact with the surface of the tuning fork causing the surface to heat up. The optical energy absorbed by the gas results in a periodic thermal expansion which is converted into an electric current via the piezoelectric effect. The purpose of this project is to develop a theoretical model of a ROTADE sensor which we will use to calculate how the signal strength of the sensor depends on the system parameters.