High speed determination of laser wavelength using Poincar\'e descriptors of speckle

TL;DR

This paper introduces a simple, high-speed method for measuring laser wavelength changes using Poincaré descriptors of speckle patterns, achieving femtometer resolution with significantly faster acquisition times.

Contribution

The authors present a novel, computationally simple approach to measure wavelength shifts with high speed and precision, surpassing previous methods in acquisition rate.

Findings

Achieved femtometer-level wavelength measurement resolution.

Reduced measurement time by two orders of magnitude.

Demonstrated potential for laser wavelength stabilization applications.

Abstract

Laser speckle can provide a powerful tool that may be used for metrology, for example measurements of the incident laser wavelength with a resolution beyond that which may be achieved in a commercial device. However, to realise highest resolution requires advanced multi-variate analysis techniques, which limit the acquisition rate of such a wavemeter. Here we show an arithmetically simple method to measure wavelength changes with dynamic speckle, based on a Poincar\`e descriptor of the speckle pattern. We demonstrate the measurement of wavelength changes at femtometer-level with a measurement time reduced by two orders of magnitude compared to the previous state-of-the-art, which offers promise for applications such as speckle-based laser wavelength stabilisation.