Purpose. Improving the method of generating vector-vortex beams using topological defects in the orientation of the optical indicatrix in liquid crystals with linear dichroism.
Specifications. The developed technology can be implemented using various liquid crystal materials. The required dichroic liquid crystal cell is obtained by adding 0.8 wt% Nile Red fluorescent dye to the optically transparent E3100-100 nematic and placing the resulting mixture in a 16.7 μm thick glass cell with a mechanically applied alignment layer. In this case, the half-width of the dichroism line of such a cell was 75 nm (in the wavelength range from 495 to 570 nm), within which the inverse dichroism parameter did not exceed 0.9. Maximum dichroism was observed at 540 nm, the inverse parameter was 0.84. When ensuring a phase difference of such a cell equal to half the light wavelength, the intensities of the vector-vortex and vortex modes are 2.6% and 70% of the intensity of the incident radiation, respectively.
Application area. Research and experimental development in the field of other natural and technical sciences; information security and cyber defense systems
Advantages. The implementation of the developed technology makes it possible to generate vector-vortex beams without using complex and high-tech optical elements in the optical circuit, such as metasurfaces with a lattice period shorter than the wavelength of optical radiation or electrically controlled spatial light modulators on liquid crystals.
Technical and economic effect. The developed technology will improve the processes of encoding information and generating images with ultra-high resolution. Its implementation will improve the coding of information in information security and cyber defense systems, which is important for increasing the defense capability of Ukraine.
Description. The technology for the formation of vector-vortex beams is based on the interaction of light beams with the optical medium, where a topological defect is created in the distribution of the orientation of the optical indicatrix. As such an optical medium, a dichroic liquid crystal is used, from which the optical cell is made. This makes it possible to form vector-vortex beams without using additional complex and high-tech optical elements in the optical circuit, such as metasurfaces with a lattice period shorter than the wavelength of optical radiation or electrically controlled spatial light modulators on liquid crystals.