E. A. Sobakinskaya

Terahertz spectroscopy of DNA

The spectra of the degraded DNA of herring are studied using two methods of THz spectroscopy that employ a femtosecond laser and a frequency synthesizer based on a BWO and a high-Q cavity. An interpretation of the experimental results is presented.

High-precision terahertz spectroscopy for noninvasive medicine diagnostics

Abstract In recent years methods for exhaled breath analysis have been developing all around the world. The exhaled breath analysis could result in a powerful tool for noninvasive medicine. The work presented in this paper is concerned with gas analyzers for exhaled breath diagnostics. The analyzers are based on high-precision spectrometers of the THz frequency range, which provide high resolution, high sensitivity and detect a wide range of detectable substances. The spectrometers work on non-stationary effects (phase-switching and fast sweep of frequency). The analyzers have been successfully applied for the detection of various biomarkers (nitric oxide, acetone, ammonia, methanol, ethanol) in the breath of conditionally healthy volunteers and patients with various cancerous and noncancerous diseases.

Using the methods and facilities of nonsteady-state spectroscopy of the subterahertz and terahertz frequency ranges for noninvasive medical diagnosis

This paper discusses ways to implement terahertz-range spectrometers based on the effects of freely damped polarization and rapid traverse of the frequency range. It presents the results of using developed spectrometers to record the presence of ammonia, acetone, and nitric oxide in exhaled air, as well as to analyze a liquid (Custodiol) for flushing transplanted parenchymatous organs.

Terahertz spectroscopy of heavy and superheavy water vapors

The paper reports on preliminary results of a study into a possibility of developing a fast method of atmospheric air analysis for the purpose of determination of the isotope composition of water vapors (H<inf>2</inf>¹⁸O, HD¹⁶O, HTO) with the method of non-stationary terahertz (THz) range spectroscopy.

Dynamics Of Interaction Of Quantum System With Stochastic Fields

Analytical and numerical calculations of dynamics of polarization and population difference for two‐level quantum system, interacting with stochastic fields are presented. For the stochastic fields we consider two cases: phase‐diffusion and colored‐noise field of arbitrary intensity. Stationary values and characteristic evolution times of polarization and population difference are defined.

Effect of stochastic fields on spectrum of two-level quantum system

Analytical and numerical calculations of spectrum of two-level system, interacting with stochastic fields are presented. For the stochastic fields we consider two cases: phase-diffusion and colored-noise field of arbitrary intensity. The special attention is given to Rytov fields.

SubTHz spectrometer based on a radiation source with stochastic phase

Principle and modes of operation of subTHz spectrometer with noise source are described.

SubTHz and FTIR spectroscopy of explosive vapors

Discussed are experimental results of subTHz vapor phase spectroscopy over solid samples of explosives, such as commercial trinitrotoluene (THT), nitroglycerine (NG) and cyclonite (RDX). The as-obtained results were compared against analyses results of the natural decomposition products of some explosives with the use of the Fourier-transform IR-spectrometry.

Analysis Of Noise Characteristics And Noise Generation In SubTHz And THz Frequency Ranges

Noise characteristics of subTHz and THz devices (mixers, detectors) based on Schottky diodes and quantum superlattice diodes (SL‐diodes) are presented. The test bench for measurements of device’s characteristics is elaborated. Noise generator of THz frequency range based on SL‐diodes multiplier and mm noise generator is also demonstrated.

The precise measurement of relaxation parameters for power-broadened microwave transitions

We report a new method for measurement of the Voigt line relaxation parameters by means of phase-switching microwave spectrometer. The method is based on the separation of the homogeneous part of line out of the experimentally obtained adsorption coefficient. It has been tested on the OCS spectrum. The method has been applied to investigation of multicomponent gas mixture.