Tunable Hybridization at Mid Zone and Anomalous Bloch-Zener Oscillations in Optical Waveguide Ladders

TL;DR

This paper investigates tunable hybridization and anomalous Bloch-Zener oscillations in optical waveguide ladders, revealing mid-zone band gaps and tunneling phenomena that enhance control over light propagation in structured optical systems.

Contribution

It introduces a novel mid-zone hybridization mechanism and demonstrates tunable Bloch-Zener oscillations in optical waveguide ladders, expanding understanding of coherent lattice phenomena.

Findings

Mid-zone band gap formation due to hybridization.

Tunable Bloch-Zener oscillations with mid-zone tunneling.

Enhanced control of light in optical waveguide structures.

Abstract

We have studied the optical oscillation and tunneling of light waves in optical waveguide ladders formed by two coupled planar optical waveguide arrays. For the band structure, a mid-zone gap is formed due to band hybridization and its wavenumber position can be tuned throughout the whole Brillouin zone, which is different from the Bragg gap. By imposing a gradient in the propagation constant in each array, Bloch-Zener oscillation (BZO) is realized with Zener tunneling between the bands occurring at mid zone, which is contrary to the common BZO with tunneling at the center or edge of the Brillouin zone. The occurrence of BZO is demonstrated by using the field-evolution analysis. The tunable hybridization at mid zone enhances the tunability of BZO in the optical waveguide ladders. This work is of general and fundamental importance in understanding the coherent phenomena in lattice structures.