Dielectric-tuned photon-photon coupling in a planar hybrid system

Abstract

This study presents photon-photon coupling (PPC) in a microwave hybrid system consisting of a Split Ring Resonator (SRR) and a Complementary Split Ring Resonator (CSRR), both acting as photon modes. Numerical simulations using CST Microwave Studio were performed to design the system and analyze the anticrossing phenomenon between the photon modes (SRR and CSRR) by examining the |S21| versus frequency spectra while varying the size of the CSRR. Additionally, we provide a theoretical framework to explain the observed anticrossing phenomenon due to photon-photon interaction, which shows strong agreement with the simulation. Furthermore, we explore the influence of the substrate's dielectric constant (εr) on the PPC by estimating the coupling constant for different εr values. The results indicate that the coupling strength decreases as εr increases, highlighting a tunable parameter for controlling photon interactions in hybrid microwave systems. This discovery opens new avenues for developing and optimizing tunable systems, which are crucial for progress in quantum technologies. © 2025 The Author(s)