Malgosia Kaczmarek

Biographie:
Malgosia graduated from the University of Poznan in Poland and then received DPhil from the University of Oxford, researching four-wave mixing processes in gaseous media. She was a research fellow at the Department of Engineering Sciences at the University of Oxford, Optoelectronics Research Centre at Southampton and the Department of Physics at the University of Exeter. In 2010 she was appointed to a personal chair at the University of Southampton. Her research on nonlinear materials and photorefractive crystals was recognised by the awards of a Royal Society Dorothy Hodgkin fellowship, followed by an EPSRC Advanced Fellowship. In 2020, Malgosia was nominated to became an SPIE Fellow.

Titre de la communication:
Harvesting Light to Control Light for Smart Liquid Crystal Systems

À propos de cette session tutorielle:
Liquid crystals (LCs) and photosensitive polymers are key examples of soft matter with subtle internal structure that can be used to control light, and which can also be rearranged and probed by light and external fields. This has made them attractive in terms of fundamental research and commercial applications, including recent advances in adaptive LC lenses and spectacles as well as AR/VR systems. A critical issue, however, is that the modification of a specific element or a desired property typically impacts other parameters. Some are intrinsic properties of the liquid crystal, either in pure form or as a colloidal suspension, e.g. the elastic constants and the viscosity coefficients. Others, like the anchoring energy and the pretilt angle, characterize the interaction between the liquid crystals and the surfaces that contain them. The former, for example, influences the threshold behavior of the device and its optical contrast between low and high voltage, and the latter determines the stability of the device. For applications, it is particularly important to measure the surface alignment properties of already assembled devices without introducing significant alterations during the measurement process. 

In this tutorial, we will discuss how light can be harvested not only to extract material and device parameters to aid the fabrication and the performance of LC devices including those geometrically thin (1-2 μm) but also control light propagation. We will also discuss the new functionalities and enhanced response achieved through light responsive substrates, including metasurfaces for THz applications. Photovoltaic-LC systems will also be covered, offering promise for a new generation of smart systems that adapt their optical properties based on the illuminating intensity and being controlled through photovoltage.