Blood testing with the SWIRSENSE laser

In recent years, the short-wave infrared (SWIR) spectral region has been increasingly adopted for use within medical imaging technologies. The ability of these lasers to operate in the SWIR range, means they can produce real-time information, with high-quality – thanks to high-speed wavelength scanning.

As part of the European Eurostars SWIRSENSE project, Brolis Semiconductors and CSEM have succeeded in pushing this technology even further, by carrying out non-invasive screening tests that are both more sensitive and more selective. This technological feat makes it possible to distinguish molecules of interest such as glucose, lactates or urea in blood via simple spectral analysis in the short-wave infrared range of between 1.7 and 2.5 μm.

A high-performance laser, at the heart of the project

CSEM took the lead in developing the laser source (with an external cavity package to sweep the wavelength), which was a key component of the project, while ensuring its compatibility with dedicated laser chips developed by Brolis Semiconductor. The result: a laser with a high spectral purity that can select a specific wavelength and scan a whole spectral range to distinguish molecules of interest from the background absorption of water – or in this case, measuring glucose, lactates or urea in blood.

Tuning the laser’s wavelength over a range greater than 200 nm – a challenge met by the project team – was achieved by tilting a MEMs micro-mirror on a pivot axis. The resulting movement enables the continuous or very precise step-by-step adjustment of a wavelength, with excellent repeatability and high speed. The mechanical resonance frequency of the micro-mirror at roughly 195 Hz allowed scanning frequencies of wavelengths in excess of 100 Hz across the entire spectral range – quickly producing a very accurate and non-invasive measurement.

Towards a better understanding of Diabetes and Metabolism Disorders

This measurement can be used to detect through the skin, serum albumin, the main protein found in blood. Thanks to its highly sensitive measurement capabilities, SWIRSENSE laser technology is paving the way towards a better understanding of medical conditions such as diabetes or liver failure.