Texas Instruments Incorporated
DIFFERENTIAL MEASUREMENT OF IR ABORPTION IN PLASMONIC MEMS SENSORS

Abstract:

A differential nondispersive infrared (NDIR) sensor incorporates an infrared (IR) chopper and multiple multi-bit digital registers to store and compare parameter ratio values, as may be digitally calibrated to corresponding temperature values, from chopper clock cycle portions in which a plasmonic MEMS detector is irradiated by the IR chopper with such values from chopper clock cycle portions in which the IR detector is not irradiated by the IR chopper. The plasmonic MEMS detector is referenced to a reference MEMS device via a parameter-ratio engine. The reference device can include a broadband IR reflector or can have a lower-absorption metasurface pattern giving it a lower quality factor than the plasmonic detector. The resultant enhancements to accuracy and precision of the NDIR sensor enable it to be used as a sub-parts-per-million gas concentration sensor or gas detector having laboratory, commercial, in-home, and battlefield applications.