The Localized Goos Hänchen Shift In Reflection And Transmission Via Sodium Atomic Medium

Abstract

In this work, we investigate the manipulation of the Goos-Hänchen (GH) shifts, referring to the lateral displacement of light beams at planar interfaces, in a global sodium atomic vapor medium by utilizing its tunable optical characteristics under the coherent control fields and the variable incident angles (0.6rad≤θ≤0.8rad). We achieve this by accurately manipulating probe detuning and control field intensities using a technique called 'electromagnetically induced transparency (EIT)'. EIT is a quantum interference effect that makes a medium transparent to a probe beam. By combining a near-resonant probe beam with transitions in the sodium atoms [D₂ line (⁵S_1/2​→⁵P_3/2)​], we obtain remarkable amplification of absorption, reflection, and transmission with spatially shifted beams that present up to ±4λ bidirectional GH shifts in reflection and ±2λ in transmission. The non-ideal normalization condition (∣T∣₂+∣R∣₂+∣A∣₂<1) results from the redistribution of energy due to these shifts and indicates that established efficiency bounds no longer apply in coherent media. The GH-shifted beams astonishingly also maintain uniform intensity profiles at large displacements. Here, then, angular-dependent reflection pivots peak around critical angles, and transmission shifts are dynamically tunable, all emphasizing the atomic susceptibility gradients as key shapers for beam steering. These observations reveal unprecedented promise in applications, such as super-precision optical measurement, sub-wavelength displacement detection, and refractive index measurement, thus making sodium atomic vapors a tunable platform for advanced photonic devices with unique and high sensitivity.

Keywords:

Goos-Hänchen shift, Sodium atomic vapor, Atomic coherence, Beam displacement sensing, Optical susceptibility modulation