Izvestiya of Saratov University.
ISSN 1817-3020 (Print)
ISSN 2542-193X (Online)


Физика

Self-mixing Interferometry of Distance at Wavelength Modulation of Semiconductor Laser

Theoretical description for method of distance measurement at alteration emission wavelength of semiconductor laser, operated in self-mixing regime, has been presented. The result of computer modeling of self-mixing signal at harmonic wavelength modulation of laser diode has been represented. Spectral harmonic selection of low-frequency spectrum of self-mixing signal for distance measurement has been theoretically substantiated.

Optical Clearing of Human Eye Sclera by Aqueous 30%-Glucose Solution

In this work, optical clearing of human eye sclera in vitro under action of aqueous 30% glucose solution was studied. It was shown that diffusion of glucose in tissue results in significant decrease of light scattering, which manifests itself in both decreasing reflectance and increasing transmittance of the samples. At that, absorption coefficient does not change. Measurements were performed with spectrophotometer CARY-2415 in the spectral range from 400 to 800 nm by a standard method.

The Liquid Crystal Modulator on the Basis of the Waveguide Mode in the Twist Structure with the High Twist Angle

On the basis of the analysis of color characteristics of different LC display units the criterion for an assessment of an unchromaticity of black-and-white images is entered. For the adequate description of the optical properties of the LC modulator the necessary set of three characteristics is offered: contrast of the modulator, average on a range; the average on a range passage of the modulator for a status «is opened»; a modulator akhromatichnost is «open» for a status.

Model of the Miniature Modulator for Microwave Devices

In the given paper the model of the miniature modulator for microwave devices is observed. The modulator consists of the master oscillator, which provides four series of the impulses, and of the inverter commutated with the surge generator providing a plate supply of the load. The pulsing plate supply of the load is stabilized by the current regulator on the unipolar transistor. The control and check unit realize the general control of the modulator. The optimal characteristic of the work of a magnetron is provided by the 16-digit microcontroller.

Comparison of Methods for Phase Synchronization Diagnostics from Test Data Modeling Nonstationary Signals of Biological Nature

Three methods of phase synchronization diagnostics from time series are compared by the analysis of test data. These data reproduce the statistics of experimental temporal realizations recorded from the system of human cardiovascular system autonomic control.

Time-delayed Feedback Control of Coherence Resonance. Experimental Study

In the paper a possibility to control the behavior of dynamic systems under conditions of coherent resonance using delayed feedback is proved experimentally. This problem is studied on the classical example of excitable system, which is the FitzHugh – Nagumo oscillator, as well as on the example of the Van der Pol oscillator with hard excitation, which also demonstrates the regime of coherent resonance. In both cases, when changing the delay time the feedback loop can both enhance and suppress the effect of coherent resonance.

Total Conversion of Terahertz Wave Polarization by Graphene Microribbon Array without Magnetic Field

The polarization conversion of terahertz radiation by the periodic array of graphene microribbons located at the surface of a high-refractiveindex dielectric substrate (prizm) is studied theoretically. Polarization conversion at the plasmon resonance frequencies takes place without applying external DC magnetic field. It is shown that giant (up to total) polarization conversion can be reached at the total internal reflection of THz wave from the periodic array of graphene nanoribbons.

On the Use of Optical Clearing in Strengthening the Sclera by Collagen Photocrosslinking

In the paper, the first evaluation results on the effect of optical clearing on the efficiency of the technique of eye sclera strengthening through the formation of riboflavin / ultraviolet collagen photocrosslinks are presented.

Compensation for Losses in a Resonant Circuit when Using Inertial Inductive and Capacitive Two-poles

Generalized linear inertial two-poles are introduced, and the eigen-oscillations are consi-dered in a series resonant LCR-circuit with a second-order inertial inductive element. It is shown that the introduction of the second order element is equivalent to entering negative damping into the resonant circuit.

Plasmonic Rectification of Terahertz Radiation in a Grating-gated Graphene

The theory of the plasmonic rectification of terahertz radiation in a homogeneous graphene gated by a metal grating with an asymmetric unit cell is developed.

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