Optical Amplification with Large Goos-H$\ddot{a}$nchen Shift Driven by Non-Hermitian Bilayer Meta-Grating Under Lasing State
Year: 2026
Type: preprint
Abstract: The coexistence of gain and loss in parity-time symmetric bilayer meta-gratings enables the transformation of bound states in the continuum into a ring of lasing threshold modes. Under lasing state, gain saturation drives the contraction of this mode ring into a single discrete lasing point. Additionally incident weak optical field with frequency and incident angle nearly matched to the lasing mode can obtain amplification accompanied by prominent Goos-H$\ddot{a}$nchen shifts. Specifically, active meta-grating with lasing mode at the $Γ$ point induce sizable Goos-H$\ddot{a}$nchen shifts. In contrast, active meta-grating with lasing mode off the $Γ$ point induce large Goos-H$\ddot{a}$nchen shifts that are proportional to the quality factor of the effective resonant modes under lasing state. In finite meta-grating, finite-size effects exert distinct influences on the lasing state as well as the Goos-H$\ddot{a}$nchen shifts of the additionally incident optical field: the lasing characteristics and Goos-H$\ddot{a}$nchen shifts of $Γ$-point lasing modes remain nearly unaffected, whereas those of off-$Γ$ lasing modes are significantly modulated by finite-size perturbations.
Source: arXiv (Cornell University)
Authors: Luo, Ma, Zhang, Xueyi
Institution: Guangdong Polytechnic Normal University
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G3917650638, G791812790
OpenAlex ID: W7166852504