Year: 2025
Type: article
Abstract: High-resolution optical sensing typically relies on complex, high-finesse interferometers, limiting the scalability and cost-effectiveness of extreme-precision metrology. We propose a simple, compact alternative: a metallic-boundary waveguide containing a single-point dielectric impurity, operated near its cutoff frequency. This device achieves ultra-high spectral resolution by exploiting Fano resonance, arising from the quantum–optical interference between the waveguide’s continuous modes and a quasi-bound state induced by the local impurity. For analytical modeling, we employ the Impurity D Function (IDF), an approach previously confined to quantum mechanical scattering, demonstrating its first application in an integrated optical system. Our analysis shows that the spectral resolution (ℜ) scales powerfully with the geometry, specifically ℜ~ε/w−12, where ε/w is the impurity-to-waveguide ratio. This translates directly into an extremely sensitive strain gauge, with transmission linearity T11=1/2+ℜη near the 50% working point (η is the mechanical strain). We calculate that for a practical ratio of ε/w≅1%, the device yields a resolution of ℜ~1020, confirming its potential to measure mechanical strains smaller than η~10−21 using a fundamentally simple, integrated platform.
Source: Photonics
Author: Er'el Granot
Institution: Ariel University
Language: English
Topic: Photonic and Optical Devices
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,896
OpenAlex ID: W7115908895