# A fibre-optic ultrasound sensor of simple fabrication

## TL;DR

A new, simple-to-make fiber-optic ultrasound sensor outperforms traditional devices in sensitivity and ease of use.

## Contribution

A novel fiber-optic ultrasound sensor with simple fabrication and superior performance compared to piezoelectric hydrophones.

## Key findings

- The sensor achieved higher sensitivity and signal-to-noise ratio than piezoelectric hydrophones.
- It offers a miniature form factor and turn-key operation with simple fabrication.
- The sensor uses a deformable and reflective structure deposited via dip-coating.

## Abstract

The small size, high sensitivity, and immunity to electromagnetic interference of fibre-optic ultrasound sensors make them highly attractive for applications in biomedical imaging and metrology. Typically, such sensors rely on optically resonant structures, such as Fabry–Perot cavities, that require elaborate fabrication techniques. Here, an alternative fibre-optic ultrasound sensor is presented that comprises a simple deformable and reflective structure that was deposited using simple dip-coating. Interrogation with a laser Doppler vibrometer demonstrated how this sensor achieved a sensitivity, signal-to-noise ratio, and noise-equivalent pressure that outperformed piezoelectric hydrophones, whilst offering a highly miniature form factor, turn-key operation, and simple fabrication.