Properties of nematic LC planar and smoothly-irregular waveguide structures: research in the experiment and using computer modeling

Nematic liquid crystal planar and smoothly-irregular waveguide structures were studied experimentally and by the computer modeling. Two types of optical smoothly-irregular waveguide structures promising for application in telecommunications and control systems are studied by numerical simulation: liquid crystal waveguides and thin film solid generalized waveguide Luneburg lens. Study of the behavior of these waveguide structures where liquid crystal layer can be used to control the properties of the entire device, of course, promising, especially since such devices are also able to perform various sensory functions when changing some external parameters, accompanied by a change in a number of their properties. It can be of interest to researchers not only in the field of the integrated optics but also in some others areas: nano-photonics, optofluidics, telecommunications, and control systems. The dependences of the attenuation coefficient (optical losses) of waveguide modes and the effective sizes (correlation radii) of quasi-stationary irregularities of the liquid-crystal layers on the linear laser radiation polarization and on the presence of pulse-periodic electric field were experimentally observed. An estimate was made of the correlation radii of liquid-crystal waveguide quasi-stationary irregularities. The obtained results are undoubtedly important for further research of waveguide liquid crystal layers, both from the theoretical point of view, and practical – in the organization and carrying out new experimental researches, for example, when developing promising integrated-optical LC sensors.The publication has been prepared with the support of the “RUDN University Program 5-100” (Sevastyanov L.A.) and funded by RFBR according to the research projects No. 18-07-00567, No. 18-51-18005 and No. 19-01-00645

Experimental and numerical study of properties of nematic liquid crystal waveguide structures

Nematic liquid crystal optical waveguide structures were studied by the numeric simulation and experimentally. Two types of optical smoothly-irregular waveguide structures promising for application in telecommunications and control systems are studied by numerical simulation and experimentally: liquid thin waveguide lens and thin film generalised waveguide Luneburg lens. The dependence of attenuation coefficient (optical losses) of the waveguide modes and the effective sizes (correlation radii) of the quasi-stationary irregularities of the liquid-crystal layer on the linear polarization of the incident laser radiation and the presence of pulse-periodic electric field were experimentally observed. An estimate is made of the correlation radii of liquid-crystal waveguide quasi-stationary irregularities. The observed decrease in the attenuation coefficient of the waveguide modes and the effective sizes of irregularities in the liquid-crystal layer, when the external electric field is switched on, explained by the effect of the decrease in the fluctuations correlation radii of the local orientation of the molecules of the liquid crystal. The obtained results are undoubtedly important for further research of dynamic processes inside non stationary waveguide liquid crystal layers, both from the theoretical point of view for understanding kinetic processes in the liquid crystals, and with practical, - in the organization and carrying out suitable experimental researches. © 2018 IEEE