Imaging-based molecular barcoding with pixelated dielectric metasurfaces
Although mid-infrared (mid-IR) spectroscopy is a mainstay of molecular fingerprinting, its sensitivity is diminished somewhat when looking at small volumes of sample. Nanophotonics provides a platform to enhance the detection capability. Tittl et al. built a mid-IR nanophotonic sensor based on reflection from an all-dielectric metasurface array of specially designed scattering elements. The scattering elements could be tuned via geometry across a broad range of wavelengths in the mid-IR. The approach successfully detected and differentiated the absorption fingerprints of various molecules. The technique offers the prospect of on-chip molecular fingerprinting without the need for spectrometry, frequency scanning, or moving mechanical parts. ; The research leading to these results has received funding from the European Research Council under grant agreement no. 682167 VIBRANT-BIO and the European Union Horizon 2020 Framework Programme for Research and Innovation under grant agreements no. 665667 (call 2015), no. 777714 (NOCTURNO project), no. FETOPEN-737071 (ULTRACHIRAL project), and no. 644956 (RAIS project). The authors acknowledge the support of the Australian Research Council.