Dmitry Alexandrovich Usanov

This paper discusses a self-mixing interferometry method for measuring distances upon sawtooth modulation of the wavelength of laser radiation. Conditions under which the distance obtained from the spectrum of the modeled autodyne signal coincides with the distance specified in computer simulation are determined. The limiting capabilities of the method are theoretically substantiated for the increased range of deviations of the laser wavelength. The estimation of the limiting capabilities of the distance measurement method on the spectrum of the autodyne signal gives 10 microns at a wavelength of 650 nm at a 5-nm deviation of laser radiation wavelength. We also discuss difficulties of attaining the limiting accuracy of distance measurements associated with the nonlinear dependence of the wavelength emitted by a laser diode on its supply current and the need to analyze the self-mixing signal at high frequencies.

Monitoring of skin blood flow oscillations related with mechanical activity of vessels is a very useful modality during diagnosis of peripheral hemodynamic disorders. In this study, we developed a new model and technique for real-time conversion of skin temperature into skin blood flow oscillations, and vice versa. The technique is based on the analogy between the thermal properties of the human skin and electrical properties of the special low-pass filter. Analytical and approximated impulse response functions for the low- and high-pass filters are presented. The general algorithm for the reversible conversion of temperature into blood flow is described. The proposed technique was verified using simulated or experimental data of cold stress, deep inspiratory gasp, and post-occlusive reactive hyperaemia tests. The implementation of the described technique will enable to turn a temperature sensor into a blood flow sensor.

In this paper, we describe a method for restoring reflector motion using a radio-wave signal from a super high frequency (SHF) autodyne generator based on a Gunn diode. The proposed method...

— A feasible design of a system with an allowed band with near-unity frequency-independent transmission utilizing the reflective properties of photonic crystals with dielectric filling and...

A waveguide Bragg structure containing equidistant cylindrical pins that are galvanically coupled to a wide wall of the waveguide is used to implement frequency response functions characterized by the presence of a band gap. Characteristics of a defect mode of the microwave photonic crystal with a pin element as a defect with an n – i – p – i – n structure with controlled conductivity placed in the capacitive gap are experimentally studied and calculated. Controlled reflectance of a microwave signal with a dynamic range of greater than 50 dB is obtained at the frequency of the defect mode.

Knowledge of the effective mass of quasiparticles is needed for studying the band structure of semiconductors, simulating processes of conductivity, and developing actual semiconductor...

The original results of theoretical and experimental studies and the properties of microwave one-dimensional waveguide photonic crystals have been generalized. Methods for describing the electrodynamic characteristics of photonic crystals and their relationship with the parameters of periodic structures filling the waveguides have been presented. The results of an investigation on the characteristics of microwave waveguide photonic crystals made in the form of dielectric matrices with air inclusions have been presented. The model of effective dielectric permittivity has been proposed for describing the characteristics of the investigated photonic crystals containing layers with a large number of air inclusions. New types of microwave low-dimensional waveguide photonic crystals containing periodically alternating elements that are sources of higher type waves have been described. The possibility of effective control of the amplitude-frequency characteristics of microwave photonic crystals by means of electric and magnetic fields has been analyzed. Examples of new applications of waveguide photonic crystals in the microwave range have been given: the measuring parameters of the materials and semiconductor nanostructures that play the role of the microwave photonic crystals' periodicity defect; the resonators of near-field microwave microscopes; small-sized matched loads for centimeter and millimeter wavelength ranges on the basis of microwave photonic crystals.