Abstract

Metasurfaces, which confine optical fields within subwavelength unit cells while simultaneously enhancing light−matter interactions, further accelerate the development of infrared technologies by enabling on-chip integration, device miniaturization, and ultrathin photonic platforms. In all-dielectric metasurfaces, surface phonon polariton (SPhP) emerges from the coupling of incident photons and transverse optical phonons, which can significantly advance the infrared nanophotonic applications. Here, choosing the polar perovskite material strontium titanate (SrTiO₃) as an example, we apply ellipsometric measurements and multiscale simulations to explore SPhP’s role in determining the in-plane thermal conduction especially at high temperatures and far-infrared detection. The spectroscopic ellipsometer measures the dielectric function of SrTiO₃ at the temperature range of 250-800 K, and multiscale simulations including first-principles, molecular dynamics and finite-difference time-domain (FDTD) are performed to understand the fundamental interactions between electrons, phonons and photons. The predicted thermal conductivity of 50-nm-thick suspended SrTiO₃ membrane can reach 20.26 W/mK at 500 K, more than two times the bulk value. On the other hand, an ultrathin hybrid dielectric SrTiO₃/Ge metasurface is demonstrated that enables efficient FIR (>20 µm) application with a high Q quality factor about 100. We also conducted a proof-of-concept polymer detection study in which the FIR mode enabled efficient thickness sensing and material identification, with thinner metasurfaces demonstrating superior performance. Our work focuses on exploring the great potential of SPhPs to enhance in-plane heat transfer and advance the development of far-infrared technologies.

Biography

Jiayue Yang has completed his PhD from Harbin Institute of Technology and postdoctoral studies from RWTH Aachen University. He works as a professor in Shandong University of China. His research interests focus on high-temperature thermal radiation, all-dielectric metasurfaces and thermal management. More than 130 pee-reviewed papers has been published and 5 patents are authorized.