Weak value amplification using asymmetric spectral response of Fano resonance as a natural pointer

TL;DR

This paper demonstrates that asymmetric Fano resonance in metamaterials can serve as a natural pointer for weak measurement amplification, broadening the scope of weak measurement techniques beyond traditional symmetric Gaussian pointers.

Contribution

It introduces the use of asymmetric Fano spectral response in metamaterials as a natural pointer for weak measurements, showcasing real and imaginary weak value amplification.

Findings

Spectral peak shifts demonstrate real weak value amplification.

Resonance line width narrows or broadens indicating imaginary weak value amplification.

The approach extends weak measurement applicability to natural spectral line shapes.

Abstract

Weak measurement enables faithful amplification and high precision measurement of small physical parameters and is under intensive investigation as an effective tool in metrology and for addressing foundational questions in quantum mechanics. Most of the experimental reports on weak measurements till date have employed external symmetric Gaussian pointers. Here, we demonstrate its universal nature in a system involving asymmetric spectral response of Fano resonance as the pointer arising naturally in precisely designed metamaterials, namely, waveguided plasmonic crystals. The weak coupling arises due to a tiny shift in the asymmetric spectral response between two orthogonal linear polarizations. By choosing the pre- and post-selected polarization states to be nearly mutually orthogonal, we observe both real and imaginary weak value amplifications manifested as spectacular shift of the peak frequency of Fano resonance and narrowing (or broadening) of the resonance line width, respectively. Weak value amplification using asymmetric Fano spectral response broadens the domain of applicability of weak measurements using natural spectral line shapes as pointer in wide range of physical systems.