Low-loss Materials for high Q-factor Bragg Reflector Resonators

TL;DR

This paper investigates how high permittivity dielectric materials with low intrinsic losses can significantly improve the Q-factor of Bragg resonator designs, enhancing their performance for high-frequency applications.

Contribution

It demonstrates that selecting low-loss, high-permittivity materials can nearly double the Q-factor of Bragg resonators compared to traditional materials.

Findings

Q-factor of 2.34x10^5 achieved with sapphire

Potential to improve Q-factor by up to a factor of 2 with better materials

Higher permittivity materials reduce dielectric energy and metallic losses

Abstract

A Bragg resonator uses dielectric plates within a metallic cavity to confine the energy within a central free space region. The importance of the permittivity is shown with a better Q-factor possible using higher permittivity materials of larger intrinsic dielectric losses. This is because the electric energy in the reflectors decreases proportionally to the square root of permittivity and the coupling to the metallic losses decrease linearly. In a sapphire resonator with a single reflector pair a Q-factor of 2.34x10^5 is obtained, which may be improved on by up to a factor of 2 using higher permittivity materials.