Topological metrology and its application to optical position sensing

TL;DR

This paper explores topological singularities as a robust foundation for optical position sensing, demonstrating how reference points linked to these singularities enhance measurement stability against system deformations.

Contribution

It introduces a topological metrology framework for optical sensors, connecting reference settings to singularities in measurement outputs for improved robustness.

Findings

Topological singularities serve as stable reference points in optical measurements.

Application to nano-position sensing shows enhanced robustness.

Generalization to image-based schemes broadens the approach's applicability.

Abstract

We motivate metrology schemes based on topological singularities as a way to build robustness against deformations of the system. In particular, we relate reference settings of metrological systems to topological singularities in the measurement outputs. As examples we discuss optical nano-position sensing (i) using a balanced photodetector and a quadrant photodetector, and (ii) a more general image based scheme. In both cases the reference setting is a scatterer position that corresponds to a topological singularity in an output space constructed from the scattered field intensity distributions.