Russian scientists have created a material with mutually exclusive properties

Photonic crystals have a unique optical properties and are characterized by a periodic structure. Photonic glass, on the contrary, have a disordered structure, but also interesting from the point of view of use in future optical devices. Is it possible to combine two mutually exclusive properties in one material? This question is answered by an international team of researchers, which includes the owner megagranta Yuri Kivshar.

It is known that Photonic crystals — Materials that can manipulate the light is already used extensively in the development of optical fibers Lasers, as well as prototypes of the functional elements of the future photonic integrated circuits. The unique properties of these materials are laid in an orderly arrangement of the elements of the crystal. It is because of ordering elements of lenses called photonic crystals crystals.

Scientists continue this analogy and suggested that in photonics, along with regular structures can be created and some amorphous, disordered material. Such material succeeded in synthesizing colloidal solution of spherical particles of polymethyl methacrylate in 2010 the team of Spanish and German scientists, who soon gave the name of this class of substances — photonic glass. In photonic glasses identical to each other forming elements form a disordered structure. It is noteworthy that its optical properties, in contrast to the photonic crystal are determined by the individual properties of lenses, rather than the orderly ensemble. These features provide the material with unique optical properties and allow the implementation of new modes of propagation of light in disordered media.

An international team of researchers from the Physico-Technical Institute. AF Ioffe RAS,Australian National UniversityLaser center in Hanover and National Research University of Information Technologies, Mechanics and Optics, which also was part of a visiting foreign scientist and winner of themegagranta Yuri Kivshar for synthesis of photonic crystals and glasses suggested using a laser.

The synthesis of nanostructures was implemented using a three-dimensional laser lithography, which consisted of layered processing photosensitive material with a laser beam. The sequential scanning laser polymerization occurs in the areas of the photoresist in which the beam is in focus, while the rest of the structure of the material remained unchanged. Then, with a developer scientists removed the material is not exposed to intense laser radiation. The very process of the beam was controlled by a complex system of positioning, which was ruled by a computer program.

The problem of synthesis of photonic glasses researchers solved in two stages. At the first stage of the method described above was obtained classical photonic crystal in which the interlayer air alternated with cylinders with a diameter of 740 nm photoresist. Successive field of air cylinders and form a periodic structure, which gave special photonic crystal optical properties.

At the second stage, the researchers modified the synthesis parameters: increased scanning speed, the power of the laser radiation and limited acceleration, the system of positioning in the horizontal plane. The result was also obtained by the periodic structure of alternating areas air cylinder, but in this case the cylinders were not homogeneous and consist of small voids and different elements.

Thus, the very structure of the periodic properties of the material on him closer to a photonic crystal and a disordered structure of the components of its cylinders — to the photon glass. Study of the optical properties of photonic kvazistekla that the type of structure is located between the two materials antagonist, is an interesting and non-trivial task, which the authors have promised to work to implement in their next article.

This work was supported RFBR (Grant № 11-02-00865), Basic Research Program of the Presidium of Russian Academy of Sciences Number 24 and a grant from the Government of the Russian Federation for government support of scientific research conducted by leading scientists at Russian institutions of higher education (Contract № 11.G34.31.0020 on November 28, 2010).

Source of information:

II Shishkin, KB Samusev, MV Rybin, MF Lemons, YS Kivshar, A. Gaydukeviychute, RV Kiyan, BN Chichkov "glassy nanostructure fabricated by laser lithography." Solid State Physics, , 2012, Volume 54, Issue 10.

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