Accurate, Efficient and Rigorous Numerical Analysis of 3D H-PDLC Gratings

This work presents recent results derived from the rigorous modelling of holographic polymer-dispersed liquid crystal (H-PDLC) gratings. More precisely, the diffractive properties of transmission gratings are the focus of this research. This work extends previous analysis performed by the authors bu...

Full description

Bibliographic Details
Main Authors: Jorge Francés, Sergio Bleda, Daniel Puerto, Sergi Gallego, Andrés Márquez, Cristian Neipp, Inmaculada Pascual, Augusto Beléndez
Format: Article
Language:English
Published: MDPI AG 2020-08-01
Series:Materials
Subjects:
Online Access:https://www.mdpi.com/1996-1944/13/17/3725
Description
Summary:This work presents recent results derived from the rigorous modelling of holographic polymer-dispersed liquid crystal (H-PDLC) gratings. More precisely, the diffractive properties of transmission gratings are the focus of this research. This work extends previous analysis performed by the authors but includes new features and approaches. More precisely, full 3D numerical modelling was carried out in all analyses. Each H-PDLC sample was generated randomly by a set of ellipsoid geometry-based LC droplets. The liquid crystal (LC) director inside each droplet was computed by the minimisation of the Frank elastic free energy as a function of the applied electric field. The analysis carried out considered the effects of Frank elastic constants <inline-formula><math display="inline"><semantics><msub><mi>K</mi><mn>11</mn></msub></semantics></math></inline-formula>, <inline-formula><math display="inline"><semantics><msub><mi>K</mi><mn>22</mn></msub></semantics></math></inline-formula> and <inline-formula><math display="inline"><semantics><msub><mi>K</mi><mn>33</mn></msub></semantics></math></inline-formula>; the anchoring strength <inline-formula><math display="inline"><semantics><msub><mi>W</mi><mn>0</mn></msub></semantics></math></inline-formula>; and even the saddle-splay constant <inline-formula><math display="inline"><semantics><msub><mi>K</mi><mn>24</mn></msub></semantics></math></inline-formula>. The external electric field induced an orientation of the LC director, modifying the optical anisotropy of the optical media. This effect was analysed using the 3D split-field finite-difference time-domain (SF-FDTD) method. In order to reduce the computational costs due to a full 3D tensorial analysis, a highly optimised method for high-performance computing solutions (HPC) was developed. The influences of the anchoring and voltage on the diffraction efficiencies were investigated, showing the potential of this approach.
ISSN:1996-1944