Resonant splitting in periodic T-shape photonic waveguides

TL;DR

This paper investigates photon resonant splitting in periodic T-shape photonic waveguides, revealing how different frequency regions produce distinct splitting patterns influenced by quasi-bound states and structural parameters.

Contribution

It introduces a detailed analysis of resonant splitting phenomena in T-shape waveguides using Green's function, highlighting the role of high quasi-bound states and structural modulation.

Findings

(n-1)-fold splitting in low frequency region

(n-2)-fold splitting in high frequency region

Splitting peaks are controllable via structural adjustments

Abstract

Resonant splitting phenomena of photons in periodic T-shape waveguide structure are investigated by the Green's function method. It is found that, except for the (n-1)-fold resonant splitting in the low frequency region, (n-2)-fold resonant splitting occurs in the high frequency region of the transmission spectra. The (n-2)-fold resonant splitting peaks are induced by the high quasi-bound states where the photons are mainly localized in the constrictions rather than in the stubs. To this kind of quasi-bound state, the stub acts as a potential barrier rather than a well, which is the inverse of the case of the low quasi-bound states corresponding to the (n-1)-fold splitting peaks. These resonant peaks can be modulated by adjusting the periodic number and geometry of the waveguide structures.