Vladimir G Volostnikov

Spiral-type beams

Abstract The existence of spiral-type beams - light fields that remain unchanged under propagation intensity neglecting scale and rotation - has been shown by theoretical means. An example of spiral-type beam experimental realization is presented. The connection between the beam shaping problem and obtained results has been considered.

Spiral-type beams: optical and quantum aspects

Abstract The existence of spiral-type beams with a predetermined intensity distribution is investigated by theoretical and experimental means. Spiral-type beams with an intensity distribution in the form of an arbitrary planar line were found. A correspondence between these laser beams and a specific quantum-mechanical situation — ground states of a charged particle in a uniform magnetic field — was found. The connection between spiral-type beams and coherent states is shown. Some methods of spiral-type beam synthesis are described. Experimental results of transformation of a gaussian beam into a triangle-line laser beam are presented.

Generation of spiral-type laser beams

Abstract It has been shown theoretically that spiral-type beams are modes of a ring resonator with a beam rotator. The generation of spiral-type beams by this technique is demonstrated experimentally.

Microobject manipulations using laser beams with nonzero orbital angular momentum

Microobject manipulation with a laser is investigated. The functional capabilities of the laser manipulators can be significantly enhanced using beams with predetermined distributions of intensity and angular momentum. Beams with nonzero angular momentum are generated using phase and amplitude-phase masks. Such beams make it possible to rotate weakly absorbing particles and to move them along a given trajectory. Experimental results on the microobject motion along various trajectories (circle, triangle contour, self-intersecting curve, and Archimedes spiral) are presented.

General astigmatic transform of Hermite-Laguerre-Gaussian beams.

The general astigmatic transform, or two-dimensional non-separable linear canonical transform of a Hermite-Laguerre-Gaussian beam, is investigated by theoretical means. Some corollaries that apply to Hermite-Gaussian and Laguerre-Gaussian beam propagation are presented and discussed.

Analysis of contour images using optics of spiral beams

An approach is outlined to the recognition of contour images using computer technology based on coherent optics principles. A mathematical description of the recognition process algorithm and the results of numerical modelling are presented. The developed approach to the recognition of contour images using optics of spiral beams is described and justified.

Capture of microscopic objects by contour optical traps formed by 4-channel liquid crystal modulator

The efficiency of the contour optical traps generated by the 4-channel liquid crystal modulator for the manipulation with both transparent and absorbing particles has been experimentally studied. The maximum velocity of the substrate movement at which the captured particle is kept in the optical trap was used for the traps efficiency estimation. The obtained data show the ability of the effective capture of transparent objects with the ring traps even in the course of the objects boundary (periphery) being under the impact. The possibilities of a smoothly control of the size and the form of optical traps for increasing of the capture efficiency have been demonstrated.

Spiral light beams: characteristics and applications

The report contains discussions of theoretical and experimental results of the study on the light beams that retain their intensity structure under propagation and focusing. We describe the behavior of a family of such laser beams called spiral beams, keeping their intensity invariant within scale and rotation, under their propagation. These very features of spiral beams are of a high practical interest for those occupied with the laser technologies and image processing. Some of the applications, in particular their use for the retrieval of the onedimensional signals phase and contour analysis are demonstrated.

Coherent States in Optics

An approach has been developed with the use of coherent states for constructing wavelets based on spiral light beams.

Wigner distribution function and intensity integral moments of Hermite-Laguerre-Gaaussian beams

Hermite-Laguerre-Gaussian (HLG) beams are recently introduced light beam family that contains Hermite-Gaussian and Laguerre-Gaussian beams as particular representatives. The Wigner function and some other integral characteristics for HLG beams are found and discussed.