Few-Layer Terahertz Metasurfaces for Enhanced Light-Matter Interactions

Chun-Chieh Chang^1*

¹Institute of Electro-Optical Engineering, National Taiwan Normal University, Taiwan

* Presenter:Chun-Chieh Chang, email:chang48@ntnu.edu.tw

The terahertz (THz) spectral region has attracted a great deal of attention over the past few decades for a wide range of potential applications including spectroscopy, imaging, chemical and biological sensing, material characterization, and wireless communications, to name a few. To date, although numerous important breakthroughs and inventions in the THz region have been made, many opportunities and challenges in the THz frequency region remain to be identified and overcome. In the past few years, metamaterials, a class of artificial effective electromagnetic media composed of periodic arrays of subwavelength metal/dielectric resonators, have exhibited exotic optical properties unattainable by naturally occurring materials. Specifically, planar metamaterials, or metasurfaces, have recently demonstrated their ability to control and manipulate the amplitude, phase, and polarization state of the THz electromagnetic waves. However, the efficiencies of single-layer metasurfaces are usually low due to their limited interaction strength with light. In this talk, I will introduce the concept of a few-layer metasurfaces, composed of a few layers of metasurfaces separated by thin dielectric spacers, which not only addresses the low efficiency issue of single-layer metasurfaces, but also allows for functionalities beyond the individual metasurfaces. I will then talk about my recent experimental developments in few-layer THz metasurfaces for applications in optical antireflection, narrow bandpass filtering, beam focusing, and polarization conversion, demonstrating their superior ability to control the THz wave with unprecedented high efficiencies.

Keywords: Metasurface, Metamaterial, Terahertz