Papers by Alexander Tavrov
Proceedings of SPIE, Feb 13, 1996
Stress factors can be visualized reliably by measurements of motion dynamics. Spatial portraits a... more Stress factors can be visualized reliably by measurements of motion dynamics. Spatial portraits and temporal diagrams of impulses from two different kinds of cells -- Physarum and Dictyostelium discoideum -- are considered in the present work. Large numbers of biological applications require development of quantitative measurements in the dimensional range of classical optics. In order to apply this, we used a 3D RM 600 AUTOFOCUS Profilometer with spatial resolution of 1 micrometer2. It allows measurement at the dynamical bands of 0.001 - 120 Hz. Perspectives and measured results as well as applications of another computer-aided microscopical technique are discussed.
Proceedings of SPIE, Jun 1, 1992
Phase object pattern analysis has shown the possibility of considerably increasing microscope spa... more Phase object pattern analysis has shown the possibility of considerably increasing microscope spatial resolution. Experiments have revealed more than ten times resolution enhancement. Some phase object images inside an Airy disk are presented.
Proceedings of SPIE, Dec 12, 1994
Optical techniques present useful tools for superresolution at 3D and surface inspection. Microsc... more Optical techniques present useful tools for superresolution at 3D and surface inspection. Microscopic analysis of phase images has shown a higher diffraction stability of some field fragments, particularly wavefront dislocations. Diffractional stability is intent for contrast- and resolution enhancement and is generalized to the case of polarization imaging. This paper develops the morphological analysis of phase- and polarization images. Several practical algorithms for obtaining superresolution are discussed.
Proceedings of SPIE, Aug 1, 1992
Some biological structures like chromosomes, mitochondria, cell walls, and living cells were obse... more Some biological structures like chromosomes, mitochondria, cell walls, and living cells were observed with the computer-aided phase microscope (CPM) `Airyscan' having spatial resolution 5 - 20 nm. We succeeded in obtaining new information about dynamic processes in living cells and micro-organisms by a new registering method. Some of the possible applications in the areas of medicine and biology are discussed.
Proceedings of SPIE, Mar 1, 1994
The question of informative character of special image points--wavefront dislocations, is discuss... more The question of informative character of special image points--wavefront dislocations, is discussed. They were observed in real phase images of microstructures, which had comparable and smaller linear dimensions than diffraction limit. According to the existing classification, phase patterns of the main types of wavefront dislocations were identified. Their influence on the phase imaging formation is investigated. The case of induced phase contrast due to considerable decrease, but not quite vanishing of the complex amplitude, is taken into consideration. The contour making and contrasting tendency in the presence of the combination of dislocations, is demonstrated. Observation of anomal small-size details in phase and polarization images and the possibility of their observation in general `functional' image, is discussed. The experimental pictures were obtained with the help of unique phase microscope `AiryScan' technique.
Pisma v Zhurnal Tekhnischeskoi Fiziki, May 1, 1989
The paper reports a new modulation technique for obtaining polarization-constrast images of trans... more The paper reports a new modulation technique for obtaining polarization-constrast images of transparent microscopic objects. A standard microscope with a 40X objective, an He-Ne laser, and an Elektronika-60 computer were used in the experiments reported. The use of advanced instrumentation made it possible to enhance the magnification of the microscope and to improve the SNR (which was about 10 in the experiments reported). Particular attention is also given to the achievement of super-Rayleigh lateral resolution in the microscope for the study of anisotropic objects.
Journal of Experimental and Theoretical Physics, Dec 1, 2008
We propose an achromatic interferometer for the observation of a faint off-axis light source agai... more We propose an achromatic interferometer for the observation of a faint off-axis light source against the background of a bright on-axis light source. The on-axis source and its copy acquire an achromatic phase shift by 180° and interfere with a phase difference of π. The achromatic phase shift is attributable to the geometric phase in the three-dimensional interferometer scheme. Interference spatially separates the nulled and bright fields of the on-axis source, redirecting them on opposite sides of the beamsplitter. Interference does not attenuate the field of the off-axis source and redirects it with an equal intensity on both sides of the beamsplitter. We consider the principle of operation of the nulling interferometer and constraints on the attenuation of an extended source due to the decrease in coherence. The laboratory breadboard and experiment are briefly described.
Астрономический вестник, 2017
Soviet Journal of Quantum Electronics, Mar 31, 1990
It is shown that a super-Rayleigh spatial resolution can be realized in a phase image of an objec... more It is shown that a super-Rayleigh spatial resolution can be realized in a phase image of an object. Measurements carried out using a computer-controlled phase microscope confirm the feasibility of determination of the coordinate of an abrupt change in the height of a semiconductor structure profile with an accuracy better than 10 nm.
Journal of Experimental and Theoretical Physics, Jun 1, 2009
We propose a new scheme of an achromatic nulling interferometer-coronagraph to gain a higher cont... more We propose a new scheme of an achromatic nulling interferometer-coronagraph to gain a higher contrast in the star-planet model. Two successive rotational shearing interferometers improve the interference contrast limited by insufficient spatial coherence of a physically extended source, a star. The theory and simulations have been confirmed by an experiment. The theoretical value of the coronagraphic contrast has been improved from 104 to 1010 for an angular size of the extended source of 10−2λ/D, where λ is the wave-length and D is the telescope’s aperture diameter.
Optical Engineering, Aug 1, 2002
Metrology, measurements, and laboratory procedures. Measurements common to several branches of ph... more Metrology, measurements, and laboratory procedures. Measurements common to several branches of physics and astronomy. Spatial dimensions (eg, position, lengths, volume, angles, and displacements). Instruments, apparatus, and components common to several branches of ...
Technical Physics, Mar 1, 2010
A common path interferometer that is intended for observation of a faint off axis light source ag... more A common path interferometer that is intended for observation of a faint off axis light source against the background of an intense on axis source is suggested. The on axis source and its replicated image acquire an achromatic phase shift of 180° and interfere in antiphase. The achromatic phase shift is due to the geometrical phase in the configuration of a 3D interferometer. Interference spatially separates the dark and bright fields of the on axis source by directing them to different sides of a beam splitter. At the same time, interference does not attenuate the field of the off axis source, directing it to different sides of the beam splitter with equal intensities. Such a configuration of the common path interferometer provides mechanical stability.
42nd COSPAR Scientific Assembly, Jul 1, 2018
Photonics
Over the past decades, the achievements in astronomical instrumentation have given rise to a numb... more Over the past decades, the achievements in astronomical instrumentation have given rise to a number of novel advanced studies related to the analysis of large arrays of observational data. One of the most famous of these studies is a study of transient events in the near and far space and a search for exoplanets. The main requirements for such kinds of projects are a simultaneous coverage of the largest possible field of view with the highest possible detection limits and temporal resolution. In this study, we present a similar project aimed at creating an extensive, continuously updated survey of transient events and exoplanets. To date, the core of the project incorporates several 0.07–2.5 m optical telescopes and the 6-m BTA telescope of the Special Astrophysical Observatory of RAS (Russia), a number of other Russian observatories and the Bonhyunsan observatory of the Korea Astronomy and Space Science Institute (South Korea). Our attention is mainly focused on the description of ...
Measurement Techniques, 2010
We propose a new matrix method for calculating geometric image rotation, taking into account the ... more We propose a new matrix method for calculating geometric image rotation, taking into account the effects of the geometric and dynamic phases in a nonplanar optical layout. In order to describe the propagation of light in this system, the algebra of two-dimensional Jones polarization vectors and matrices in two-dimensional space is extended to three-dimensional space. We give practical examples of nonplanar layouts of polarization nulling interferometers for application in astronomy and precision wavefront analysis.
Soviet Journal of Quantum Electronics, 1990
It is shown that a super-Rayleigh spatial resolution can be realized in a phase image of an objec... more It is shown that a super-Rayleigh spatial resolution can be realized in a phase image of an object. Measurements carried out using a computer-controlled phase microscope confirm the feasibility of determination of the coordinate of an abrupt change in the height of a semiconductor structure profile with an accuracy better than 10 nm.
SPIE Proceedings, 1992
Phase object pattern analysis has shown the possibility of increasing considerable microscope spa... more Phase object pattern analysis has shown the possibility of increasing considerable microscope spatial resolution. Experiment has revealed resolution enhancement of greater than a factor of ten. Some phase object images inside an Airy disk are presented.
SPIE Proceedings, 1992
Some biological structures like chromosomes, mitochondria, cell walls, and living cells were obse... more Some biological structures like chromosomes, mitochondria, cell walls, and living cells were observed with the computer-aided phase microscope (CPM) `Airyscan' having spatial resolution 5 - 20 nm. We succeeded in obtaining new information about dynamic processes in living cells and micro-organisms by a new registering method. Some of the possible applications in the areas of medicine and biology are discussed.
SPIE Proceedings, 1990
Previous measurements with computer-aided phase microscope using Linnik scheme with a dissector a... more Previous measurements with computer-aided phase microscope using Linnik scheme with a dissector as coordinate sensitive detector showed an opportunity to obtain superdiffractional resolution d Other Conferences Other 0 1990-03-01|1990-04-30 The Hague '90, 12-16 April HA90 3264 The Hague, Netherlands Industrial Inspection II 1265 Techniques and Instrumentation
SPIE Proceedings, 1992
Phase object pattern analysis has shown the possibility of considerably increasing microscope spa... more Phase object pattern analysis has shown the possibility of considerably increasing microscope spatial resolution. Experiments have revealed more than ten times resolution enhancement. Some phase object images inside an Airy disk are presented.
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Papers by Alexander Tavrov