Microwave Plasmonic Exceptional Points for Enhanced Sensing

The emergence of exceptional points in a non-Hermitian system has provided intriguing possibilities to enhance the sensitivity of a sensor, while it is yet a considerable challenge to implement subwavelength non-Hermitian systems. One possible solution to tackle this challenge is to take advantage of localized surface plasmon resonances, which enable large electromagnetic enhancement at the subwavelength scale. In this work, a novel sensing scheme based on the exceptional points in a spoof plasmonic structure working at microwave frequencies is proposed. It is shown that near-field plasmonic vortices can be efficiently generated at the exceptional points, resulting in the enhanced sensitivity when detecting a single particle or fluid analytes. Single particle detection with the particle size as small as 1/100 of the operating wavelength is reported. For liquid analysis in the microfluidic system, the sample consumption is down to 0.72 & mu;L. This work demonstrates the ultrahigh sensitivity of exceptional-point-based plasmonic sensing and opens up new possibilities for subwavelength and compact sensors operating in the microwave, terahertz, and even far-infrared regions.

Automated summary

The emergence of exceptional points in non-Hermitian systems provides possibilities for enhancing sensor sensitivity, but implementing subwavelength non-Hermitian systems remains a challenge. One potential solution is to use localized surface plasmon resonances, which enable large electromagnetic enhancement at the subwavelength scale. In this work, a novel sensing scheme based on exceptional points in a spoof plasmonic structure at microwave frequencies is proposed, demonstrating ultrahigh sensitivity and opening possibilities for compact sensors in the microwave, terahertz, and far-infrared regions.