A major advancement in the way of measuring of laser light could revolutionize quantum and medical technologies, according to a new report in the journal Nature Communications.
The breakthrough is a new way to measure the scattering of laser light by a rough surface and it could lead to a superior new type of laser wavemeter.
Wavemeters can establish the wavelength of a particular light and these devices are useful in a wide range of scientific disciplines. All atoms and molecules process light at exact wavelengths. Therefore, the capacity to identify and change laser light at high resolution is critical in various applications, from the identifying chemical samples to measuring the energy of individual atoms.
Light waves, like waves of water, interact by way of a phenomenon known as interference: If two waves interact while each one is at a peak, the outcome is a bigger wave, but if a peak of one wave hits the trough of another wave, the outcome is a smaller wave. The sum of these effects generates an interference pattern, which has significant value for scientists.
Typical wavemeters evaluate transformations in an interference pattern using high-precision optical components. Wavemeters found in the typical research facility can cost tens of thousands of pounds or more.
The study team said they were able to discover a reliable and low-cost device which exceeds the resolution of all commercially-available wavemeters. The development was accomplished by pointing laser light into a 5-cm diameter white sphere, and documenting the nature of the light that shot out through a small hole in the sphere, with the pattern of light being very responsive to the wavelength of the laser.
Study author Graham Bruce, an optics professor from University of St Andrews, said you can see the basic principle that the new development is based on by shining a laser pointer on a wall in your home. Bruce said you should observe a grainy or speckled spot, 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,” Bruce said in a statement. “This speckle pattern might seem of little use but in fact the pattern is rich in information about the illuminating laser.
“The pattern produced by the laser through any such scattering medium is in fact very sensitive to a change in the laser’s parameters and this is what we’ve made use of,” he added.
The team said their development could open up a new pathway for ultra-precise measurement of laser light, with a degree of accuracy close to one part in three billion, or about 10 to 100 times more precise than commercial units now available.
The team also revealed that this hypersensitive capability might be used to actively control the wavelength of a laser. This precise laser control could have massive implications for quantum technology applications and biomedical research studies.
M Squared Lasers, an optics research company that partnered with the St. Andrews team on the study, is currently investigating a wide range of cutting edge applications for extremely accurate lasers. The M Squared research might be used in all kinds of new scientific frontiers, such as regenerative medicine, where stem cells are used to regrow damaged or diseased organs made from a patient’s own genetic material.
University of St Andrews