Статья посвящена крупному ученому и организатору науки, профессору Льву Михайловичу Блинову, посвятившему свою жизнь исследованию жидких кристаллов и организованных молекулярных структур. Лев Михайлович является основателем школы экспериментальных исследований органических пленок и жидких кристаллов в Советском Союзе, им воспитаны десятки молодых ученых, ставших кандидатами и докторами наук. Л.М. Блиновым написаны сотни научных статей, множество обзоров, монографий и учебников, читались лекции как в России, так и по всему миру. Кратко изложена биография Льва Михайловича, дан обзор его наиболее значимых достижений и отдельных публикаций, получивших широкий резонанс в научном сообществе. Приведены воспоминания учеников и коллег.

An increase in the electro-optical switching speed with a decrease in the electrode grating period is observed in a cell with a homeotropically oriented nematic liquid-crystal (LC) layer and interdigitated electrodes. There are two modes in the electro-optical response: fast and slow. A numerical simulation has shown that the fast mode occurs because of the LC director deformation in the surface layer. On the contrary, the occurrence of slow mode is due to the fact that the deformation propagates much more slowly in the LC bulk. The observed effect has been demonstrated experimentally in the bidirectional switching mode using two crossed interdigitated electrodes, located at both sides of the LC layer.

The electrooptics in the bidirectional field switching mode in a homeotropically aligned layer of a nematic liquid crystal with two pairs of interdigitated microelectrodes situated on the opposite sides of the cell has been studied in detail. The method of bidirectional field switching eliminates the slow stage of free relaxation of liquid crystal (LC) molecules and makes it possible to approach a submillisecond speed of electro-optical switching. The electro-optical characteristics studied in the geometry with parallel interdigitated electrodes are compared with the previously obtained data for a cell with mutually orthogonal electrodes.

Hybrid optical nanostructures composed of metallic nanoslit gratings and functional organic material are studied. Interdigitated aluminum grating covered with a nematic liquid crystal is shown to exhibit unprecedentedly fast thresholdless electro-optical switching due to the liquid crystal realignment within a thin surface layer. Coating subwavelength silver slit gratings with Langmuir-Blodgett films of azo-dye compound enables the low-intensity optical control of their extraordinary light transmission by photo-induced optical anisotropy.

Combined with liquid crystals, plasmonic nanostructures acquire voltage-driven optical tunability. We report that light-transmitting interdigitated aluminum grating covered with a nematic liquid crystal exhibits fast electro-optical switching: for the visible light wavelengths above the surface-plasmon resonance, its switching is thresholdless and, being driven by a voltage of a few volts, occurs on a time scale of tens of microseconds. We relate these features to the fast liquid crystal realignment within a thin surface layer that controls the plasmon excitation and light transmission.

Optical vortices were generated by means of photoinduced point defects in orientation of the nematic liquid crystal (NLC). The axisymmetric distribution of NLC director field was produced due to photorefractive effect in NLC or due to isotropic channel formation in light absorbing NLC.

The electro-optic effect in hybrid structures based on subwavelength metallic nanogratings in contact with a layer of a nematic liquid crystal has been experimentally studied. Metallic gratings are fabricated in the form of interdigitated electrodes, which makes it possible to use them not only as optical elements but also for the production of an electric field in a thin surface region of the layer of the liquid crystal. It has been shown that, owing to the electric-field-induced reorientation of molecules of the liquid crystal near the surface of the grating, it is possible to significantly control the spectral features of the transmission of light, which are caused by the excitation of surface plasmons. The electro-optic effect is superfast for liquid crystal devices because a change in the optical properties of the system requires the reorientation of molecules only in a very thin surface layer of the liquid crystal.

We demonstrate a new fast electro-optical switching mode in homeotropically-aligned layer of a nematic liquid crystal. The electric field spatial distribution in the LC layer is switched between twisted-planar and normal states by means of driving the electric potentials over a system of interdigitated electrodes, which have mutually orthogonal orientation at the top and bottom sides of the LC layer. A twisted-planar field characterized by twisted spatial distribution induces a twisted state of the LC, whereas switching back to the homeotropic state is driven by a normal field that is oriented along the LC layer normal. The bidirectional driving eliminates the stage of free relaxation to the homeotropic state, thus allowing for very fast electro-optical switching between the optical states: total switching time is less than 1 ms, which is an order faster than for the conventional twist effect in nematics. The advantages of the suggested driving mode include gradual grayscale and deep-black state that is due to initial homeotropic alignment with a zero pretilt angle.

Two electrooptical effects in a system consisting of subwavelength aluminum gratings and a nematic liquid crystal (LC) layer are discussed. The aluminum gratings produced by a focused ion beam lithography act as interdigitated electrodes, which allows application of an electric field to a very thin fraction of LC layer contacting the grating. The first of the electrooptical effects is associated with an enhanced TE-polarized light transmission of the gratings and the surface induced twist deformation in the bulk of the LC layer, whereas the second one is caused by an influence of the electrically driven LC surface layer on the plasmonic resonance and the related dip of the TM-polarized grating transmission. Besides the different polarizations, the two effects have dramatically different response times. In the case of the plasmonic effect, the measured response time is found to be of 20 - 30 microseconds that is three orders of magnitude faster compared to the switching based on the surface induced twist effect.

We have studied the alignment of a nematic liquid crystal (LC) material on aluminum subwavelength nanogratings as a function of the period, p, and the slit width to period ratio, w/p. A method, based on Fourier analysis of the transmittance spectra of the LC grating system, has been applied. We show that the gratings provide stable planar alignment only for shorter periods and narrower slits (p < 400 nm, w/p < 2/3). As these parameters increase, the homogeneous surface alignment changes to domains with different tilt angles or to spatially modulated alignment. We have also obtained a 90° twisted LC director distribution, implying sufficiently strong azimuthal LC anchoring at the grating surface.

We demonstrate field-induced 2D-photonic liquid crystals (LC). The 2D spatially periodic modulation of the LC director field is achieved using a geometry with two crossed interdigitated systems of electrodes located at opposite sides of the LC layer. With a special method of dual-field driving, a very fast switching between different spatially periodic LC director distributions is achieved. The director field distribution and potential use of these photonic crystals for fast switched multidirectional lasing is discussed.

Transmission of planar layers of cholesteric liquid crystals is studied in pulsed electric fields perpendicular to the helix axis at normal incidence of both linearly polarized and unpolarized light. Spectral and light polarization properties of the primary photonic band and the field-induced bands up to fourth order of Bragg selective reflection are studied in detail. In our experiments we have achieved an electric field strength several times higher than the theoretical values corresponding to the critical field of full helix unwinding. However, the experiments show that despite the high strength of the electric field applied the helix does not unwind, but strongly deforms, keeping its initial spatial period. Strong helix deformation results in distinct spectral band splitting, as well as very high field-induced selective reflectance that can be applied in lasers and other optoelectronic devices. Peculiarities of inducing and splitting the bands are discussed in terms of the scattering coefficient approach. All observed effects are confirmed by numerical simulations. The simulations also show that liquid crystal surface anchoring is not the factor that prevents the helix unwinding. Thus, the currently acknowledged concept of continuous helix unwinding in the electric field should be reconsidered.

It is demonstrated that an optical beam acquires a component with spiral dislocation of wave front (optical vortex) due to passage through a layer of homeotropically aligned nematic liquid crystal with light-absorbing admixture. The vortex is formed owing to the heating of liquid crystal and transition to isotropic phase in the irradiated region, which leads to the generation of axisymmetric field distribution of director at the interface of the isotropic channel and nematic liquid crystal.

The orienting effect of light on nematic liquid crystals (NLCs) doped with comb-shaped polymers with different spatial distributions of side absorbing azobenzene fragments, i.e., a homopolymer (containing only azofragments), a block copolymer (containing additionally a block of non-absorbing fragments), and a statistical copolymer (containing randomly arranged absorbing and non-absorbing fragments) is experimentally studied. The light-induced Freedericksz transition threshold for the block copolymer is two times lower than that for the homopolymer. For NLC with statistical copolymer dopant, the first-order orientation transition with an extremely wide optical bistability region is observed.

It is proposed to apply the birefringence method to measure the threshold of the light-induced Freedericksz transition and the nonlinearity enhancement factor of nematic liquid crystals by director relaxation dynamics in the light field. A birefringence change is recorded by interference of ordinary and extraordinary components of the light beamaffecting the liquid crystal director orientation. The Freedericksz transition thresholds and nonlinearity enhancement factors are measured for the samples doped with comb-shaped polymers with various degrees of polymerization. The determined thresholds are in agreement with the results obtained by the aberrational self-action method.

The effect of compensation for the spectral dispersion of light polarization states at the output of a single-domain layer of a chiral liquid crystal (CLC) is experimentally studied. It is shown that such dispersion can be decreased significantly with the aid of phase plates of two types that have different signs of the spectral dispersion of birefringence. The dispersion compensation allows one to significantly increase the operating spectral range of fast light modulators based on chiral nematic liquid crystals (NLCs).

The effect of the induction and "triplet" splitting of intense selective reflection bands has been experimentally revealed in chiral liquid crystals in a pulsed electric field. The effect is associated with the strong deformation of the helicoid of a chiral liquid crystal in the pulsed field and with the conservation of its step even at field amplitudes exceeding the critical field of the untwisting of the cholesteric helix. Intense polarization-sensitive light reflection bands appear in the spectral ranges where higher orders of selective reflection are forbidden for the unperturbed chiral liquid crystal.