PhD Student

Last application date
Feb 12, 2021 00:00
Department
TW06 - Department of Electronics and Information Systems
Contract
Limited duration
Degree
Master of Science in Engineering (Physics, Photonics or Electrical) or Master of Science in Physics
Occupancy rate
100%
Vacancy type
Research staff

Job description

Vacancy for a PhD candidate at Ghent University “Application of liquid crystal configurations by photoalignment“

Promotor: Kristiaan Neyts, Liquid Crystals and Photonics Group, Faculty of Engineering, Ghent University Liquid crystals (LCs) are organic soft materials that can self-organize into complex structures and are strongly responsive to external stimuli. Recently there has been a rapid development in high-resolution photo-alignment patterning by illuminating a photo-sensitive material with linearly polarized blue light. This approach has been used to produce optical axis gratings, in which the phase delay for circularly polarized light is proportional to the azimuthal angle of the alignment. These gratings can have a very high efficiency (>99%) for the first diffraction order.

In 2020 Inge Nys won the Facebook Reality Labs Crystal Research Diamond Award for her work in this field. In January 2021 a Flemish/Slovenian joint project on this topic has been funded by the FWO. With a spatial light modulator (SLM), it is possible to generate patterns with variable azimuthal polarization. By using well-chosen orientation patterns at the top and bottom substrate of a LC cell, complex structures in the LC bulk can be obtained. Recently our group has realized many complex three-dimensional LC structures based on photo-alignment with nematic LC or chiral LC and studied them with polarization microscopy.

The first objective of this PhD is the realization of liquid crystal structures by patterned photo-alignment using a spatial light modulator. We have published several designs, but there are many plans for novel structures and functionalities. The structures, and their behavior under influence of an applied voltage, will be observed with the polarization microscope to determine their nature.

The second objective of this PhD is the verification of the realized 3D director patterns by comparison with Q-tensor simulations. We will use a simulation tool based on Matlab code that is able to find director patterns that match the elastic properties of liquid crystal and the alignment imposed at the surfaces. The elasticity theory of liquid crystals is based on different types of deformations of the director: splay, twist and bend. When electric fields are applied, electrical energy becomes a competing factor.

You will design devices, realize the photo-alignment procedure with the spatial light modulator, fill the devices with LC, measure the optical properties with the polarization microscope and perform numerical simulations to analyze the structures that have been realized.

Starting date: flexible, spring or summer 2021

Job profile

We are looking for a candidate with a strong background in physics to become member of our dynamic and international research team.

Good insight in spatial geometry, experience with optical setups, and programming in Matlab and/or Python are valuable assets for these tasks.

How to apply

Submit your CV and a short letter of interest to kristiaan.neyts@ugent.be.