RESUMEN
This paper studies the dynamic response characteristics of the scanning angle in a liquid crystal cladding waveguide beam scanner. Based on liquid crystal dynamic theory, finite element analysis and vectorial refraction law, a dynamic response calculation model of scanning angle is constructed. The simulation results show that the dynamic responses of the scanning angle during the electric field-on and field-off processes are asymmetric, and exhibit "S"-shape and "L"-shape changing trends, respectively. In addition, by comparing with the bulk phase modulation response process of traditional liquid crystal devices, the intrinsic physical reason for the rapid light regulation of the liquid crystal cladding waveguide beam scanner is clarified to be that the liquid crystal close to the core layer has a faster rotation speed during the electric field-off process. Moreover, the liquid crystal cladding waveguide beam scanner is experimentally tested, and the experiment results are in good agreement with theoretical simulations.
RESUMEN
What we believe to be a novel integrated circular polarization dynamic converter (CPDC) is proposed based on the four-layer mirror symmetry structure. By designing the twisted structure and rearranging the orientation direction of liquid crystal molecules for each layer, the application wavelength range could be broadened. For the viewing angle expansion, negative birefringent films are selected to compensate for the retardation deviation under oblique incidence. Finally, the particle swarm algorithm is used to optimize the whole configuration, and the polarization conversion efficiency calculated by the finite element method (FEM) can achieve 90% in the wavelength range from 320â nm to 800â nm at an ultrawide view of 160°. Compared with traditionally active liquid crystal waveplates, the design has potential advantages in both wavelength and field of view (FOV) and provides the possibility for the integrated and flimsy fabrication of devices.
RESUMEN
This paper proposes an extended prism coupling analysis method to accurately analyze the coupling structure of liquid crystal (LC) cladding waveguide beam steerer. We analyze the effects of LC anisotropy on the coupling of transverse electric (TE) and transverse magnetic (TM) modes and derive the expression of the optical field distribution that perfectly matches the given coupling structure. Based on this method, we present the optimal coupling structure for Gaussian beam. Taking into account the practical manufacturing process, we propose a simplified coupling structure and perform a detailed analysis of its performance based on numerical simulations. Experimental results show a coupling efficiency of 91% and a coupling angle full width at half maximum (FWHM) of about ±0.02°, demonstrating the effectiveness of the proposed method in predicting the coupling performance of anisotropic cladding waveguides.
