High-resolution, flexible, and transparent nanopore thin film sensor enabled by cascaded Fabry–Perot effect

This Letter reports a method to significantly improve the optical resolution of the anodic aluminum oxide (AAO) nanopore thin film sensor based on multi-cavity Fabry–Perot interference. The newly designed sensor is fabricated by bonding a layer of transparent polymer thin film (pTF), which is polydimethylsiloxane (PDMS), to a transparent AAO thin film to form a flexible pTF-nanopore sensor. In comparison with the AAO nanopore thin film sensor, the pTF-nanopore sensor shows a much-improved quality (Q) factor and optical resolution. Typical thicknesses of a PDMS layer and an AAO layer of the pTF-nanopore sensor are 80 μm and 2 μm, respectively. The pTF-nanopore sensor used for angle detection shows a sensitivity of 0.4 nm/deg with a resolution of 0.2 deg. The pTF-nanopore sensor can also be used for temperature monitoring with a sensitivity of 0.2 nm/°C and a resolution of 1°C.