In most cases, chaotic working conditions prevent us from doing the right job. However, with this reversal of common wisdom, a team of researchers at the University of Adelaide and the University of St Andrews in Scotland have achieved a recent breakthrough in accuracy measurements by “scrambled” laser light.
The team was led by Professor Kishandrakia, a collaborator at the University of Adelaide’s Faculty of Biological Sciences and the University of St Andrews’ Faculty of Physics and Astronomy.
“This approach will advance optical and quantum sensing technologies, improve the performance of next-generation sensors, and lead to new measurement devices that may have a variety of applications, including healthcare.”
Professor Kishan Dholakia collaborated with Morgan Facchin and Dr. Graham Bruce at the University of St Andrews.
“We scrambled the light into a coarse pattern called’speckle’, using either fiberglass that is the width of human hair or a hollow sphere that bounces off many times before the light appears,” Dholakia said. The professor says.
The principle of speckle can be easily shown visually.
“Pointing a laser pointer on a rough surface, such as a painted wall or matte adhesive tape, scrambles the light from the laser into a grainy speckle pattern,” says Professor Dholakia.
“Usually I think scrambling a signal means losing information, but that’s not the case here. Moving the laser dramatically changes the exact pattern displayed. Select a speckle. It is the sensitivity to this change that is suitable for this. Precision measurement. “
Work already done by the team uses these speckle patterns wavelength-Also colour— Of light with attometre accuracy. This is equivalent to measuring the length of a soccer field with the same accuracy as the size of one atom.
In the latest advances, the team measured using speckle Refractive index Of gas. The index of refraction of a material indicates how fast light travels within the material, and this change in index of refraction can be used to look for subtle changes in the properties of the material.
Write in the journal ACS PhotonicsThe team reported measurement Change the index of refraction of air to one billionth. This is an order of magnitude improvement over the previous speckle-based approach.
Small changes in the index of refraction can have a significant impact on sensing. For example, infection can result in levels of red blood cell refractive index that can be easily detected by this sensor. The team hopes to do this not only in healthcare, but also in field portable sensors for a variety of applications, such as detecting trace gases and low concentrations of chemicals in liquids.
Morgan Facchin et al, Measuring gas index variability with a resolution of 10-9 using a laser speckle, ACS Photonics (2022). DOI: 10.1021 / acsphotonics.1c01355
University of Adelaide
Quote: The research team obtained a “scramble” laser beam from https: //phys.org/news/2022-02-team-breakthroughs-precision-scrambling-laser.html on February 22, 2022 (2022). (February 22nd) achieved a breakthrough in accuracy measurement
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The research team has achieved breakthroughs in precision measurements by “scrambled” laser light.
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