High-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:mi>Q</mml:mi></mml:math> Mie resonators for refractive-index sensing
Esmaeel Zanganeh, Zarina Sadrieva, Polina Kapitanova, Andrey Bogdanov
Abstract
Refractive-index sensors have been used in a wide range of applications, including biological diagnosis and therapy, material analysis and shaping, (bio)chemical sensing, environmental monitoring, and many more. A good sensor should have sufficiently high sensitivity and figures of merit to detect the slightest changes in the environment. Here, we study the performance of high-$Q$ Mie modes of dielectric cylinders with ultrahigh permittivity for refractive-index sensing. First, we experimentally demonstrate the emergence of high-$Q$ Mie modes in the scattering spectrum of a single dielectric cylinder with ultrahigh permittivity ($\ensuremath{\epsilon}\ensuremath{\approx}40--100$). We also investigate the sensitivity of the high-$Q$ Mie modes to the background refractive index of the surrounding environment. The simulation results demonstrate that the high-$Q$ Mie modes are sensitive to changes in the surrounding refractive index. This results in high sensitivities and remarkable figures of merit, indicating their potential for refractive-index sensing applications. However, the material losses limit the observation of high-$Q$ modes and their sensing capability.