Ewa Gorecka is affiliated with Warsaw University, Department of Chemistry. Her group specializes in characterization of soft matter structure. Her main interests are: chiral liquid crystalline structures build of achiral molecules, hybrid inorganic–organic structures, polar phases, gels and complex structure of polymers. She is an expert in applying X-ray techniques to study soft matter. She has published over 300 articles. 

Education

• 1985–Feb. 1992 (PhD) Department of Chemistry, University of Warsaw, Warsaw, Poland
• 1980–May 1985 (MS) Department of Chemistry, University of Warsaw, Warsaw, Poland

Appointments

• 2010–date, Head of Laboratory of Dielectrics and Magnetics, Department of Chemistry, University of Warsaw, Poland
• 2018–2019, Visiting Fellow at Advanced Light Source at Lawrence Berkeley National Laboratory, US
• 2001–2002, Visiting professor at CNRS, Strasbourg, France
• 2000–2001, Visiting professor at Chalmers Technical University, Sweden
• 1994–1995, Researcher at Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic

Honors

• 1990, Japanese Applied Physical Society award for the participation in the discovery of the antiferroelectric liquid crystals
• 2018, Prime Minister award for research related to soft matter
• 2020, The G. W. Gray Medal, British Liquid Crystal Society, GB
• 2020, The Foundation for Polish Science Prize – an individual prize for eminent researchers

International responsibilities

• Chair of the Awards Committee, International Liquid Crystal Society
• Associate editor of Soft Matter (Royal Society of Chemistry, GB)
• Member of Editorial Board of Liquid Crystals (Taylor & Francis Group, GB)

One of the most intriguing phenomena in liquid crystals is the spontaneous ordering of electric dipoles—referred to as ferroelectricity. Ferroelectric properties in liquid crystalline phases were first discovered in the 1970s and, for two decades, were believed to be intrinsically linked to molecular chirality. The emergence of long-range dipole order in smectic layers was attributed to the absence of inversion symmetry elements in systems composed of chiral molecules. The discovery of ferroelectricity for achiral, bent-core molecules introduced a new perspective on the relationship between polarity and chirality. In these systems, polarization arises due to steric constraints that restrict molecular rotation. Interestingly, in such systems the polarization vector, in combination with the tilt direction and the layer normal, defines either a left- or right-handed coordinate system—leading to spontaneous emergence of structural chirality, even though the constituent molecules themselves are achiral. This finding demonstrated that although the molecular chirality is not a prerequisite for ferroelectricity in liquid crystals, a connection between ferroelectricity and chirality persists. A major breakthrough came with the discovery of proper ferroelectricity in the least-ordered liquid crystalline phase—the nematic NF phase [1,2] - and subsequently in certain smectic phases as well. For strongly polar molecules, with dipoles moment >10D, dipole–dipole interactions alone could give rise to ferroelectric order. For a time, it appeared that in proper ferroelectric liquid crystals chirality and ferroelectricity were independent phenomena. However, in 2024, a pivotal discovery revealed that helicity can also emerge spontaneously as a mechanism to minimize macroscopic polarization - once again linking chirality and ferroelectricity [3]. This finding reestablishes connection between the polar order and chirality, helical structures can be induced purely through electrostatic interactions in achiral, strongly polar systems. In this context, the properties of helical nematic and smectic phases formed by achiral but strongly polar mesogenic molecules will be discussed, as well as the complexities introduced by molecular chirality. Both basic and advanced experimental techniques used to probe the structure and polar properties of these phases will be presented, including non-resonant and resonant X-ray diffraction, optical and atomic force microscopy (AFM), dielectric spectroscopy, and more. Acknowledgments: This work was funded by NCN UMO-2024/53/B/ST5/03275 References: [1] H. Nishikawa, et al., Adv. Mater. 29, 1702354 (2017). [2] R.J. Mandle, S.J. Cowling, J.W. Goodby, Phys. Chem. Chem. Phys. 19, 11429–11435 (2017). [3] J. Karcz, et al., Science 384, 1096–1099 (2024).

Masanori Ozaki received his B.E., M.E. and D.E. degrees from Osaka University in 1983, 1995, and 1988. He joined Department of Electronic Engineering in Osaka University as a research associate in 1988, and was promoted to an Associate Professor in 1994 and to a Professor in 2005. He stayed in Physics Department at University of Utah from 1994 to 1995 as a visiting scientist. He is currently a member of the Board of Trustees and Vice President of Osaka University.

 

He has been engaged in a wide range of research from fundamental properties to functional applications, including:

- The relationship between molecular structure of ferroelectric liquid crystals composed of chiral smectic phases and their dielectric properties, phase transition phenomena, smectic layer alignment characteristics, high-speed electro-optical effects, and applications to optical communication and optical information processing devices.

- Optical propagation properties and functional applications of self-organized nanostructures based on chiral liquid crystals and nanostructures fabricated using top-down processes. Light emission enhancement and laser action in photonic crystals, and wavefront control of light in metamaterials and metasurfaces.

-Modulation spectroscopy, time-resolved spectroscopy, Raman spectroscopy, and nonlinear optics of π-conjugated molecules, polymers, and liquid crystals.

- Solar cells, transistors, and OLEDs using molecular and polymer semiconductors and perovskite materials

- Fabrication and properties of highly oriented functional thin films using printing processes of π-conjugated molecules and polymers

Even if each individual molecule has a permanent dipole moment, generally each dipole cancels out and does not show macroscopic polarization, and polarization is observed only when an external electric field is applied. This is called paraelectricity. Normal liquid crystals, such as the nematic phase, exhibit paraelectricity, and the molecules change orientation in response to an external electric field using a torque based on their anisotropy as the driving force. On the other hand, when a material has a certain special symmetry or when individual dipole moments interact with each other, macroscopic polarization may occur even in the absence of an electric field. Such a state is called ferroelectricity. In the past, it was believed that ferroelectricity does not occur in fluid materials such as liquid crystals, but ferroelectricity has been observed in chiral smectic liquid crystals and banana-type liquid crystals. Furthermore, in recent years, ferroelectricity has been observed in nematic liquid crystals with high symmetry, which has attracted considerable attention. In systems with a certain symmetry, macroscopic polarization may occur when a strain or strain gradient is applied to a material. The former is called piezoelectricity and the latter is called the flexoelectric effect. When a material has macroscopic polarization, it exhibits interesting and very useful properties in terms of applications, such as piezoelectricity, pyroelectricity, and second-order nonlinearities. Especially, in the case of liquid crystals, it is very interesting to expect huge piezoelectricity and electrostriction effects due to their fluidity and viscosity. In this lecture, I will introduce macroscopic polarization observed in various liquid crystals and discuss their evaluation methods and potential applications.

Janusz Parka, Ph. D., D. Sc., Eng, Full Professor

Institute of Applied Physics, Department of Advanced Technology and Chemistry, Military Academy of Technology, Head of Photorefractive LC and Metamaterials Group, Warsaw, Poland.

 

MS, Engineer (Physicist), 1977; PhD, 1983; DSc, 2001; Prof., 2003–present.

 

Institute of Applied Physics, Military University of Technology Physics, Assistant, Adjunct, Full Professor (1977–present). And at the same time Professor in Institute of Optoelectronics and Microelectronics, Department of Electronics and Information Technology Warsaw University of Technology (2002–2019). Member of Scientific Councils in Department of Electronics and Information Technology (2003–2019). Member of Scientific Council of Department of Chemistry and Advanced Technology Military University of Technology. Head of Electrooptic Liquid Crystal an Metamaterials Group. Author and co-author of nearly 140 scientific papers. Promotor of 7 PhD Thesis.

 

Studies of electrooptical effects in liquid crystals, specially color effects in liquid crystals “guest–host system” with azo and anthraquinone dyes, properties and other physical phenomena of Twisted and Supertwisted, Chiral Nematics, technological problems with orientation and surface processes for display applications. The effects of main interest: optical and nonlinear phenomena in doped liquid crystals, photorefraction processes in thin liquid crystal layers, reorientation of LC molecules by light, dynamic holography, optical data storage and information processing. Optical recording of polarization grating recording in chiral nematics and smectics. For 12-year investigations of metamaterials, tunable transducers with liquid crystals, tunable hyperbolic metastuctures. Applications of metamaterials for photonic devices like tunable phase shifters, antenna and multiband filters.

Photonic applications of liquid crystals – selected topics J. Parka Institute of Applied Physics, Military University of Technology, Warsaw, Poland *corresponding author, e-mail: janusz.parka@wat.edu.pl First applications of liquid crystals were displays. Many devices use liquid crystals which we call Liquid Crystal Displays (LCD). But liquid crystals (nematics and smectics) found many other photonic applications in different LC devices. In order to construct highly-developed photonic systems, it is required that physical properties such as refractive index and absorption of materials are controlled by such stimuli as electric, magnetic or optical fields. Then input information carried by light wave can be modulated in its amplitude, polarization, wavelength, phase or direction This lecture will be focusd on three or four topics like: 1. Electrically and optically addressed liquid crystal spatial light modulators (OASLMs) are key elements in real-time holographic devices. Their implementation for beam steering and hologram formation will be briefly discussed. The OASLMs can be employed for construction of optical amplifiers, correlators, phase conjugate mirrors, coherent-to-incoherent image converters and adaptive optics systems. There is also a great progress in ferroelectric LC-based devices due to their short response times about 1 μs. 2. Until recently, terahertz radiation was an undeveloped area in telecommunication.. Since few years, intense work on technologies is in progress, aiming at extending capabilities of nowadays used systems to transfer data at short distances. However, the higher the frequency, the tougher the forming of mutually coherent emitters. Therefore, for this region, using a LC-based device is a good option, as in this case it allows for beam steering. THz range (0.2 – 0.4 THz) with the aim to expand research to higher frequencies to proof is a new concept. In contrast to mechanical beam steering approaches, non-mechanical LC-based beam steerers can be lightweight, compact, consume low amounts of power and inexpensive. 3. NLCs with high birefringence, small losses with metamaterial structures give possibility to increase radiation. Hyperbolic metamaterials (HMMs) are special class of engineered metamaterials which exhibit hyperbolic dispersion for interactions with electromagnetic waves, and they possess non-trivial electromagnetic properties depend on the spatial projection of their nanostructure. Nematic liquid-crystal mixture containing a fluorescent dyes like Rhodamine B and other antraquinons can be used to enhance the emission. Investigation of hyperbolic metamaterials with NLCs for spontaneous emission engineering and modification of plasmonic metasurfaces are very promising. The fascinating research field of liquid-crystal–based photonic applications is rapidly evolving and the emerging devices are likely to become key components to perform manipulation of light. Aknowledgmet: This work was supported by the European Project MERA-NeET.3, NCN/07-308/2024/ /WAT

Xabier Quintana is professor at the Polytechnic University of Madrid (UMP). He has developed his activity in the ETSI of Telecommunications of the UPM since 1993. His research interest has focused on Guided Optical Communications (anisotropic waveguides, unconventional fibers), unguided Optical Communications (atmospheric transmission, space), Photonic Applications of Liquid Crystals (displays, micro-displays, phase devices, tunable filters, modal lenses) and organic electronics (OLEDs).

 

He is co-author in more than 50 international publications in scientific journals with an impact index. He has made more than 150 communications to international conferences. He is also co-inventor of 8 patents and he has directed  7 doctoral theses, most of them in liquid crystal technology.

 

He has developed graduate and postgraduate teaching activities, mainly at the Higher Polytechnic School of the Carlos III University of Madrid (1997–98) and since then at the Higher Technical School of Telecommunications Engineers of the UPM and at the Higher Technical School of Civil Engineers of the UPM (Graduate in Materials Engineering). He has taught about 10 undergraduate subjects of different Study Plans, and as many postgraduate degrees in Doctorate and Masters. He is co-author of several Handbooks of Laboratory Practices. He has participated in several educational innovation projects.

 

Prof. Quintana has given lectures, courses and seminars, mainly on optical communications and liquid crystal devices.

In many research laboratories, efforts are focused on developing liquid crystal devices. Most of these are so-called phase devices, which alter the phase of light without changing its amplitude—unlike traditional displays. However, the fabrication processes for both types of devices share many common steps. Phase devices can sometimes be quite complex, either due to the intricacy of the electrode designs or the alignment patterns required for proper liquid crystal orientation. This tutorial aims to provide a comprehensive overview of the entire fabrication process: from electrode lithography and alignment techniques to assembly and electrical driving systems. Special emphasis will be placed on the finer details that are often hard to find in the literature i.e. ITO and FTO dry etching, photoalignment or photopatterning of polyimide. Finally, a common bottleneck in small research labs is the electrical excitation of these devices, often requiring expensive and sophisticated driving systems. This tutorial also presents simple and cost-effective solutions, such as using D/A converters for purely analog control or LED drivers combined with analog switches for PWM (pulse-width modulation)-based excitation. The goal is to help students who are just beginning to work in the field of liquid crystal devices fabrication. They could learn practical tips and tricks that would otherwise take countless hours of trial and error to discover on their own.