Loss-induced performance limits of all-dielectric metasurfaces for terahertz sensing

Abstract

Metasurfaces providing resonances arising from quasi-bound states in the continuum have been proposed as sensors in the THz band due to the existence of strong resonances characterized by high quality factors. Controlling geometrical parameters, the quality factor can be adjusted and, theoretically, designed at will. However, losses in materials critically bound the metasurface performance and limit the quality factor of the resonances. For this reason, all-dielectric metasurfaces have been proposed as an alternative to metal-dielectric structures to reduce losses and achieve extreme functionalities. When implemented by low-loss materials, these structures are usually considered lossless and proposed as ultrasensitive sensors in the THz band. In this paper, we examine the effect of losses in all-dielectric metasurfaces considering realistic materials and study the limitations in the quality factor. In addition, we compare the performance of these structures as sensors with a nanostructure supporting extraordinary optical transmission. Our results show that material loss, even in low-loss materials, severely limits the sensing performance in all-dielectric metasurfaces, and that their performance can be surpassed by structures supporting extraordinary optical transmission.

arXiv comment10 pages, 7 figures

References in corpus (6)

• Sharp dark-mode resonances in planar metamaterials with broken structural symmetry
• Ultrasensitive THz sensing with high-Q Fano resonances in metasurfaces
• Perfect control of reflection and refraction using spatially dispersive metasurfaces
• Terahertz sensing of 7nm dielectric film with bound states in the continuum metasurfaces
• Dielectric Metamaterials with Toroidal Dipolar Response
• All-dielectric resonant metasurfaces with a strong toroidal response

Cited by in corpus (1)

• Extreme nonreciprocity in metasurfaces based on bound states in the continuum