RT Journal Article
T1 Virtual spectral selectivity in a modulated thermal infrared emitter with lock-in detection
A1 Santalices, David
A1 Meléndez Sánchez, Juan
A1 Briz Pacheco, Susana
AB The need for affordable low-power devices has led MEMS-based thermal emitters to become an interesting option for optical gas sensors. Since these emitters have a low thermal mass, they can be easily modulated and combined with a lock-in amplifier for detection. In this paper, we show that the signal measured by a lock-in amplifier from a thermal emitter that varies its temperature periodically can have different spectral profiles, depending on the reference signal used. These virtual emitters appear because the Fourier series expansion of the emitted radiance, as a function of time, has different coefficients for each wavelength, and this spectral signature, which is different for each harmonic, can be retrieved using a reference signal that corresponds to its frequency. In this study, the effect is first proved theoretically and then is measured experimentally. For this purpose, we performed measurements with an IR camera provided with six different spectral filters of a modulated emitter, in combination with lock-in amplification via software. Finally, we show a potential application of this effect using multiple virtual emitters to gain spectral selectivity and distinguish between two gases, CO2 and CH4.
PB MDPI
SN 1424-3210
YR 2022
FD 2022-07-02
LK https://hdl.handle.net/10016/37043
UL https://hdl.handle.net/10016/37043
LA eng
NO This article belongs to the Section Optical Sensors
NO This work has been supported by the Madrid Government (Comunidad de Madrid-Spain) under the Multi-annual Agreement with UC3M in the line of Excellence of University Professors (EPUC3M14), and in the context of the V PRICIT (Regional Programme of Research and Technological Innovation). The authors acknowledge FEDER/Ministerio de Ciencia, Innovación y Universidades Agencia Estatal de Investigación for financial support under project RTI2018-099825-B-C33.
DS e-Archivo
RD 29 jun. 2024