# Tunable Goos–Hänchen Shift in Symmetric Graphene-Integrated Bragg Gratings

## TL;DR

Researchers designed a graphene-integrated optical device that can produce a large and tunable spatial shift of reflected light, which could be useful for sensors and adaptive optics.

## Contribution

A novel graphene-integrated Bragg grating design achieves a record GH shift of 1766λ through tunable parameters like graphene chemical potential.

## Key findings

- A GH shift of 1766λ was achieved in symmetric graphene-integrated Bragg gratings.
- The GH shift direction and magnitude are controllable via graphene chemical potential and grating geometry.
- The design could enable high-sensitivity refractive index sensors or adaptive optical devices.

## Abstract

We theoretically analyze the spatial Goos-Hänchen (GH) shifts in symmetric Graphene-Integrated Bragg Gratings (GIBGs), where monolayer graphene arrays act as tunable input/output couplers, and a periodically inserted dielectric layer forms a resonant cavity. By optimizing the cavity design, we achieve a GH shift of 1766λ, surpassing the conventional limit of hundreds of wavelengths under single-parameter tuning. The direction and magnitude can be actively controlled by the graphene’s chemical potential, grating geometry, or dielectric thickness. This mechanism may enable high-sensitivity refractive index sensors or adaptive optical devices.