High-Q plasmonic infrared absorber for sensing of molecular resonances in hybrid lead halide perovskites

• Main Authors: Dayal, Govind, Solanki, Ankur, Chin, Xin Yu, Sum, Tze Chien, Soci, Cesare, Singh, Ranjan
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2017
• Subjects: Chemical compounds; Plasmons
• Online Access: https://hdl.handle.net/10356/85455; http://hdl.handle.net/10220/43716
• Institution: Nanyang Technological University

Plasmonic resonances in sub-wavelength metal-dielectric-metal cavities have been shown to exhibit strong optical field enhancement. The large field enhancements that occur in sub-wavelength regions of the cavity can drastically boost the performance of microcavity based detectors, electromagnetic wave absorbers, metasurface hologram, and nonlinear response of the material in a cavity. The performance efficiencies of these plasmonic devices can be further improved by designing tunable narrow-band high-Q cavities. Here, we experimentally and numerically demonstrate high-Q resonances in metal-dielectric-metal cavity consisting of an array of conductively coupled annular and rectangular apertures separated from the bottom continuous metal film by a thin dielectric spacer. Both, the in-plane and out of plane coupling between the resonators and the continuous metal film have been shown to support fundamental and higher order plasmonic resonances which result in high-Q response at mid-infrared frequencies. As a sensor application of the high-Q cavity, we sense the vibrational resonances of an ultrathin layer of solution-processed organic–inorganic hybrid lead halide perovskites.