School of Physics and Astronomy

Search site

Prof Helen F Gleeson

Head of School of Physics
Soft Matter Group

Contact details

Room: 9.53
Tel: +44 (0)113 3433863
Email: H.F.Gleeson @ leeds.ac.uk
Email: headphys @ leeds.ac.uk (Head of School of Physics)

Keywords

Liquid Crystals
Photonic Materials
Devices
Sensors
Soft Matter
Self assembly

Research interests

My research concerns self-ordering and self-assembling materials, particularly liquid crystal phases. I'm an experimentalist and use a variety of approaches to understand liquid crystal structures - I aim to determine how the nanoscale properties of complex molecules affect their macroscopic physics.

Much of my work involves understanding liquid crystal systems with reduced symmetry (for example chiral or biaxial phases), both in the bulk and in devices. I have investigated biological systems as well as synthetic liquid crystal materials and an important part of my research is to understand how liquid crystals can be used for novel photonic devices and applications. I have developed novel experimental techniques to study these complex, self-organising materials and optically active media. The new experimental approaches I have developed include time-resolved and resonant x-ray scattering at synchrotrons and a variety of optical and electro-optical measurements (Raman scattering, Kerr effect etc.). These allow a deep insight into systems that show ferroelectric, ferrielectric and antiferroelectric properties, blue phases and unusual nematic systems.

Liquid crystals are perhaps best known for their use in display devices and I'm very interested developing new applications. I produced the first graphene-based liquid crystal device in collaboration with the Profs. Geim and Novoselov, who won the Nobel Prize for their discovery of graphene. I have worked on light sensitive (photochromic) materials and laser tweezers for transferring the angular momentum from light to liquid crystal droplets. Using liquid crystal physics to inform the study of biological systems provides a very powerful approach to understanding complex systems, for example the methodology normally used to predict the optics of liquid crystal devices provided a physiologically realistic mechanism for the perception of polarized light in vertebrates. Our most recent work on devices has led to the invention of switchable contact lenses in which the voltage-induced change in refractive index of the liquid crystal lens element causes a change in focus, equivalent to putting on reading glasses! Liquid crystals are intriguing and fun with much scope for both challenging fundamental physics and inventive new devices.