In this new lab we are interested in the study of liquid crystals. These fascinating materials share some properties of liquids and some properties of solids: they can flow like liquids but their components can orient in space along a uniform direction, like solids. Their orientation can be manipulated in many ways and this give rise to many interesting effects. Our research will develop in two main directions.
Optics of liquid crystal defects
Liquid crystals are widely used in LC displays when they are “well-behaved”, i.e. when they are uniformly aligned. However in some cases the boundaries may prevent their spontaneous alignment. In this case liquid crystals form topological defects, small regions where they are disordered. While topological defects are a common feature across many fields in physics, liquid crystals are quite unique in the sense that defects can be seen and detected just using optical microscopy.
Defects can interact with light in interesting ways and they can be used to form self-assembled micro-lasers, resonators or lenses (see for example: Serra, Gharbi et al., Adv. Opt. Mater. 2013).This interaction, in turn, can shed light to the nature of the defect itself.
We are interested in looking at various types of liquid crystals and find a “catalogue” of possible optical components made of reconfigurable and moldable liquid crystal defects.
These are some examples of systems we are looking at:
- defects at the smectic to chiral nematic phase transitions in confined geometries
- regular arrays of defects in nematics and smectics
- liquid crystal blue phases
Living cells as liquid crystal materials
Many types of living cells are elongated and tend to align with each other, just like liquid crystals. We study analogies and differences between the behavior of single layers of cells and liquid crystals, focusing especially on the behavior near topological defects, i.e. the regions of misalignment of cells. This provides special insights in the principles behind cells self-organization and in possible mechanisms for the formation of 3D structures in living systems.
This is our preprint on this topic: https://arxiv.org/abs/1912.03271