We study both experimentally and theoretically modulation of light in a planar aligned deformed-helix ferroelectric liquid crystal (DHFLC) cell with subwavelength helix pitch, which is also known as a short-pitch DHFLC. In our experiments, the azimuthal angle of the in-plane optical axis and electrically controlled parts of the principal in-plane refractive indices are measured as a function of voltage applied across the cell. Theoretical results giving the effective optical tensor of a short-pitch DHFLC expressed in terms of the smectic tilt angle and the refractive indices of the ferroelectric liquid crystal (FLC) are used to fit the experimental data. The optical anisotropy of the FLC material is found to be weakly biaxial. For both the transmissive and reflective modes, the results of fitting are applied to model the phase and amplitude modulation of light in the DHFLC cell. We demonstrate that if the thickness of the DHFLC layer is about $50\mu \text{m}$, the detrimental effect of field-induced rotation of the in-plane optical axes on the characteristics of an axicon designed using the DHFLC spatial light modulator in the reflective mode is negligible.

Results are presented from studying the formation of different configurations of microscopic objects using structured optothermal traps. The dynamic rearra

The presented here technique is developed for in vitro estimation of the influence of external conditions on the deformation ability of human red blood cells. The method is based on the use of single-beam laser trap for capturing of erythrocytes fixed to the bottom of the liquid cell by the adhesion force. The approach is suitable for evaluation of the properties of individual cells as well as for real-time acquisition of the data on ensemble of erythrocytes large enough for subsequent statistical analysis. It is shown that both a change in the saline solution concentration and presence of certain stabilizing agents lead to measurable shift of the maximum of the cells distribution by their deformability.

A multi-channel liquid crystal modal wavefront corrector is presented and the manufacturing procedure, which was developed especially for this type of corrector, is described in detail. An experimental analysis of the static and dynamic properties of the corrector and the results of close-loop wavefront correction are also presented.

Results of experiments on wavefront formation using multichannel modal correctors in an adaptive optical system with feedback are reported. Two types of correctors, one based on a glass substrate with a high-resistance layer deposited onto it and the other based on a high-permittivity ceramic substrate, are developed and investigated. The results show that it is expedient to use the correctors in applications that do not require a high speed of response.

The possibilities of annular optothermal trap to capture and manipulate transparent micrometer-sized objects have been investigated both experimentally and