Making the most of interference: new applications of laser speckle

Activity: Talk or presentation typesInvited talk


Take a laser pointer, and shine it through sellotape or on a rough surface like a painted wall. On closer inspection of the illuminated surface you’ll see that the spot itself looks grainy or speckled, with bright and dark patches.  This so-called “speckle pattern” is a result of interference between the various parts of the beam which are reflected differently by the rough surface. This is regarded as a randomization process which destroys information contained within the initial beam and is deleterious to many optical systems. Indeed, many engineers study speckle to remove its effect. Intriguingly however, the processes that produce the speckle are entirely linear, and there is growing recognition that this complex pattern is rich in useful information on both the incident laser source and the environment, with startling potential uses. I will demonstrate our recent results, which show that speckle can be used as a sensitive probe of wavelength changes of the light, with a resolution below 1fm, and how this can be used to stabilize the wavelength of the source.
Period4 May 2017
Held atSchool of Physics and Astronomy
Degree of RecognitionLocal