Towards fully integrated photonic displacement sensors

TL;DR

This paper presents a novel integrated photonic displacement sensor utilizing directional emission of Huygens dipoles, achieving high position accuracy suitable for on-chip applications in nanotechnology.

Contribution

It introduces the first prototype of an integrated displacement sensor based on dipolar antenna emission with demonstrated high precision.

Findings

Position accuracy below λ/300 achieved

Sensor operates effectively at room temperature

Supported by theoretical calculations confirming performance

Abstract

The field of optical metrology with its high precision position, rotation and wavefront sensors represents the basis for lithography and high resolution microscopy. However, the on-chip integration - a task highly relevant for future nanotechnological devices - necessitates the reduction of the spatial footprint of sensing schemes by the deployment of novel concepts. A promising route towards this goal is predicated on the controllable directional emission of the fundamentally smallest emitters of light, i.e. dipoles, as an indicator. Here we realize an integrated displacement sensor based on the directional emission of Huygens dipoles excited in an individual dipolar antenna. The position of the antenna relative to the excitation field determines its directional coupling into a six-way crossing of photonic crystal waveguides. In our experimental study supported by theoretical calculations, we demonstrate the first prototype of an integrated displacement sensor with a standard deviation of the position accuracy below $\lambda$/300 at room temperature and ambient conditions.