E. L. Bubis

A method for obtaining inverted images

A method for obtaining a brightness-inverted image of opaque objects is described. The factor of conversion of images from negative into positive was up to 350% relative to the average intensity level of the incident beam, which is in agreement with numerical calculations.

A simple phase-contrast scheme for observing transparent objects

A simple phase-contrast scheme, based on a photothermal cell, for observing transparent objects is described. A good visualization quality is shown for some objects, including those in a scattering medium.

A phase-contrast scheme with a Zernicke photothermal cell for visualization of ultrasonic waves

A standing ultrasonic wave is visualized by the phase-contrast method using a Zernicke photothermal cell. The good-quality visualization is implemented without expanding and collimating a probing beam.

Visualization of transparent microinhomogeneity in the nonlinear optical crystals by phase-contrast technique with adaptive photothermal Zernike filter

Visualization of growth-sector boundary and point defects in non-linear optic crystal (KDP) was performed by phase-contrast method with adaptive photothermal Zernike filter.

Use of adaptive nonlinear Zernike filter in phase-contrast technique for registration of weak absorption of the medium

The use of photothermal Zernike phase-contrast filter for measuring the absorption of the medium proposed. Results of numerical simulation are given. It is shown that the efficiency is comparable to the imaging scheme that uses linear filters, with a significant simplification of the process of its adjustment.

About zemike method visualization of transparent structures by laser beam reflection from thin layer of oil by thermo-capillary convection

The Zernike method visualization of transparent objects by laser beam reflection from thin layer of oil by thermo-capillary convection was investigated. The experiments were performed in the low-power (sub mW) level laser radiation.

Image processing by means of orientational self-action of light in nematic liqud crystal

The Zernike method using a nematic liquid crystal (NLC) filter with orientational optical nonlinearity was applied to visualize phase objects. It was shown that the contrast sign of the image switches by means of varying the incidence angle of a light beam on liquid crystal cell. The comparison of a contrast sign change of opaque object in the schemes based on NLC-filter and on liquid filter with thermal optical nonlinearity was performed.

Numerical simulation of image inversion of small-scale opaque object by the phase contrast technique with adaptive nonlinear Kerr filter

Numerical simulation of the process of inversion of the small-scale image of the object in phase-contrast scheme with nonlinear Kerr filter described.

Zernike filter based on orientational optical nonlinearity of liquid crystalline systems

Visualization of the phase object with the use of a phase-contrast scheme incorporating a nonlinear Zernike filter was carried out. A liquid crystal or liquid crystalline polymer doped with azobenzene dye inducing orientational optical nonlinearity was used as the filter. Inversion of the image contrast depending on the angle of incidence of the light beam on a nematic liquid crystal cell was implemented.

Contrast inversion by focusing laser beam in an absorbing medium

Method for obtaining an inverted brightness image of opaque objects is described. Obtained transformation to a positive image up to 350%, relative to the intensity of the incident beam, is in agreement with numerical calculations.