Laboratory of Molecular Spectroscopy
The Laboratory of Molecular Spectroscopy was one of three laboratories the Institute consisted of when it was established in 1956. The organizer and the first head of the Laboratory was Doctor of Phys. and Math. Sciences, Professor Anatoly Korshunov. From 1980 till 2004 it was headed by Vasily Shabanov (since 2003 the Full Member of Russian Academy of Sciences). The current head of the Laboratory is Doctor of Phys. and Math. Sciences Victor Zyryanov
The basic directions of the Laboratory activity are optics and spectroscopy of condensed molecular media, materials and devices of optoelectronics. The researchers of the Laboratory have obtained the following important scientific results.
Methods of determination of effective molecular polarizabilities and local field tensors in molecular crystals have been developed. Basing on study of intermolecular interactions in crystals, the fact of change of molecular polarizabilities at the transition from free to crystal state has been established. The fundamental equations of crystal optics have been obtained that allow to calculate optical properties and open the prospect of synthesis of materials with unique characteristics (refraction index, nonlinear susceptibilities, intensity of lines, order parameter and its dispersion in liquid crystals, elastic constants). The new type of phase transitions in crystals caused by nonlinear oscillation resonance has been found and the role of noncentral interactions has been clarified. To describe optical properties of crystals with modulated structure the method of selection rules calculations for optical and spectral processes has been developed. This approach has predicted the appearance of nonzero wave vector phonons in optical spectra, confirmed by experimental observation. New mechanisms of phase matching have been proposed in these media that provides ways to increase the efficiency of laser frequency conversion.
The relation of local electromagnetic field anisotropy with molecular and macroscopic parameters of liquid crystals (LC), their orientation and translation ordering, as well as with a character of intermolecular correlations, has been investigated. The local field effects in refractometry, absorption spectroscopy, Raman scattering of light and LC luminescence have been considered. Experimental approaches to determination of local field parameters in LC have been suggested and realized. Optical and spectral studies of molecular properties, structure and phase transitions in LC have been carried out. The steric effect of substituents in mesogenic molecules has been studied in terms of its influence on form and conformation of molecules, their polar and electronic properties, molecular ordering and intermolecular interactions, thermodynamic and physical properties of LC.
The theory of propagation of electromagnetic waves in one-dimensional photonic crystals, localized modes on structural defects, propagation of surface waves has been developed. The influence of defects, impurities and inhomogeneities on spectra of transmission, reflection, luminescence and nonlinear effects near photonic crystal band gaps has been studied.
The Laboratory researchers have accomplished the following significant applied developments:
- high-sensitive devices for quantitative chemical analysis of surface roughness introduced to production;
- a number of multifunctional optoelectronic materials and devices based on uniaxially oriented films of composite LC;
- the interferometer on contra directional light modes for nonlinear measurements and special photodetectors of interference field.
The main scientific publications are as follows:
- Zhizhin G.N., Mavrin B.N., Shabanov V.Ph. Optical vibrational spectra of crystals. Moscow: Nauka, 1984.
- Botvich A.N., Podoprigora V.G., Shabanov V.Ph. Raman scattering of light in molecular crystals. Novosibirsk: Nauka, 1989.
- Vetrov S.Ya., Vtyurin A.N., Shabanov V.Ph. Vibrational spectroscopy of incommensurate crystals. Novosibirsk: Nauka, 1991.
- Averyanov E.M. Local field effects in optics of liquid crystals. Novosibirsk: Nauka, 1999.
- Averyanov E.M. Steric effects of substituents and mesomorphism. Novosibirsk: Publishing house of SB RAS, 2204.
- Shabanov V.Ph., Vetrov S.Ya., Shabanov A.V. Optics of real photonic crystals. Liquid crystal defects and inhomogeneities. Novosibirsk: Publishing house of SB RAS, 2005.
- Prishchepa O.O., Shabanov A.V., Zyryanov V.Ya. Director configurations in nematic droplets with inhomogeneous boundary conditions. Phys. Rev. E, 2005, vol. 72, No 3, 031712.