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Russian and Australian scientists count particles in photon crystals with laser technique

Photon crystal shined with a laser ITMO press service
Photon crystal shined with a laser
© ITMO press service

MOSCOW, August 9. /TASS/ Scientists from Russia and Australia have put forward a novel and elegant way of counting microscopic particles in optical materials by means of a laser. They have shown that a light beam passing through such a material splits and forms a characteristic pattern on a projection screen by which the structure of the material can be recalled, as reported by the press service of Informational Technologies, Mechanics, and Optics (ITMO) University.

Photonic crystals are artificial materials which can control the propagation of light waves. With such crystals, one can change the polarization of light, focus, scatter, and amplify optical signals in microschemes, lasers, and oncoming quantum computers. However, fabricating optical materials with desired properties is a laborious process that needs constant improvement.

A research team from ITMO University, Ioffe Institute, and Australian National University for the first time has suggested analyzing the structure of photonic crystals using the optical diffraction method. An investigator should simply expose a crystal to a laser beam and then by looking at the generated light pattern count scattering microscopic particles, the particular type of defects needed to change the crystal properties.

Now, the properties of photon crystal could only be explored by means of electron or atomic-force microscopies. To do so, the target "lens" under study is coated with the metal layer, hence the properties of the sample are changed. The new method is a much more affordable alternative and, additionally, does not spoil the sample. “Even a schoolboy can use the new method to shine through the photon crystal by means of the laser pointer and small lens," comment the developers of the new technique.

The number of scattering particles and their mutual arrangement are predetermined by the properties of a crystal. For instance, if a nanolens focusing green light to a beam is needed, the defects in the crystal lattice should be separated by 500 nanometers.

The researchers believe that the structure and shape of optical materials can be recalled now without using expensive electron or atomic-force microscopies. This will allow for faster development of new optical devices. The study has been was published in Scientific Reports (