IMAging-Based Terahertz Fingerprint Sensing Using a Bi-Material Microcantilever Focal Plane Array

This paper presents an innovative imaging-based terahertz (THz) fingerprint sensing technology utilizing a bi-material microcantilever focal plane array (FPA). The microcantilever FPA is divided into <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$5\times 5$</tex> zones, with each zone integrated with a metamaterial absorber (MA) operating at a specific frequency within the range of 2~3.95 THz. Due to these frequency-specific responses, microcantilever pixels in different zones exhibit varying degrees of thermomechanical deflection under the illumination of the same THz wave, enabling the acquisition of spectral information across 25 channels. An optical readout system simultaneously captures the deflections of all pixels and converts them into a barcode-like pixel matrix image, thereby establishing a one-to-one correspondence between the THz spectral characteristics and the spatial distribution of the pixel matrix. Leveraging the fabricated microcantilever FPA and an image processing algorithm, THz fingerprint sensing of L-glutamine was successfully achieved by capturing spectral information at 2.52 THz.