High responsivity IR sensing based on reflectometric RF MEMS.

Area of Science:

• Photonics and Micro-devices
• Infrared Spectroscopy and Sensing

Background:

• Radiofrequency microelectromechanical systems (RF MEMS) integrated with metasurfaces are emerging platforms for spectrally selective infrared (IR) sensing.
• Conventional IR detectors rely on tracking resonance frequency shifts, which can limit performance and tunability.

Purpose of the Study:

• To introduce and validate a novel reflectometric approach for IR sensing using RF MEMS resonators.
• To demonstrate enhanced sensing metrics, including high responsivity and spectral selectivity, by monitoring RF MEMS input impedance.

Main Methods:

• Integration of RF MEMS resonators with metasurfaces.
• Development of a reflectometric detection scheme monitoring changes in RF MEMS input impedance.
• Coupling a reconfigurable matching network to the RF MEMS resonator to tune performance.

Main Results:

• Achieved IR responsivities exceeding 11,400 V/W (>200 A/W) with a 50-Ω readout.
• Demonstrated exceptional spectral selectivity with a full-width at half-maximum (FWHM) of 0.54 μm at 5.94 μm.
• Reported a noise-equivalent power (NEP) of ~450 pW/√Hz, a time constant of ~552 μs, and the ability to resolve IR power levels down to ~740 pW.

Conclusions:

• The reflectometric RF MEMS detector offers a reconfigurable, spectrally selective, and scalable platform for advanced on-chip IR spectroscopy and sensing.
• This approach overcomes limitations of conventional methods by utilizing input impedance monitoring for superior IR detection.
• The demonstrated performance metrics highlight the potential for high-performance, integrated IR sensing applications.