A5068245776- Liquid Crystal Research Advancements
- Photonic Crystals and Applications
- Photonic and Optical Devices
- Plant Reproductive Biology
- Advanced Materials and Mechanics
- Semiconductor Lasers and Optical Devices
- Nonlinear Dynamics and Pattern Formation
- Advanced Optical Imaging Technologies
- Optical Polarization and Ellipsometry
- Molecular spectroscopy and chirality
- Nonlinear Photonic Systems
- Phase-change materials and chalcogenides
- Optical Coatings and Gratings
- Orbital Angular Momentum in Optics
- Nonlinear Optical Materials Studies
- Photorefractive and Nonlinear Optics
- Advanced Fiber Optic Sensors
- Electrowetting and Microfluidic Technologies
- Surfactants and Colloidal Systems
- Optical Wireless Communication Technologies
- Adaptive optics and wavefront sensing
- Advanced optical system design
- Mechanical and Optical Resonators
- Plant and animal studies
- Advanced Fiber Laser Technologies
University of Oxford
2016-2025
Science Oxford
2007-2024
Brandeis University
2009
University of Strathclyde
2000
University of Exeter
1989-1998
Interface (United States)
1994
Interface (United Kingdom)
1989-1991
Skyrmions are topologically protected quasiparticles, originally studied in condensed-matter systems and recently photonics, with great potential high-density information storage. Despite the recent attention, most optical solutions require complex yet produce limited topologies. Here we demonstrate an extended family of quasiparticles beyond normal skyrmions that controlled compact photonic gradient-index media, extending to higher-order members such as multiskyrmions multimerons,...
Abstract Fiber Bragg gratings (FBGs) are ubiquitous as sensors for a range of parameters and also optical components in telecommunications systems. However, their temperature dependence around +10 pm °C −1 is limiting factor, making it challenging to discriminate strain from temperature, while require additional thermal stabilization. The temperature‐dependent properties fiber micro‐engineered by creating microchannels within the cladding using femtosecond laser‐assisted etching. These...
Organic–inorganic perovskites are highly promising solar cell materials with laboratory-based power conversion efficiencies already matching those of established thin film technologies. Their exceptional photovoltaic performance is in part attributed to the presence efficient radiative recombination pathways, thereby opening up possibility light-emitting devices. Here, we demonstrate optically pumped amplified spontaneous emission (ASE) at 780 nm from a 50 nm-thick CH3NH3PbI3 perovskite that...
Abstract Conventional polymer dispersed liquid crystal (PDLC) films have been successful as electrically‐switchable screens for privacy applications. However, spatial patterning of the so to generate a visually appealing design, logo, or image typically requires intricate fabrication processes, such use prefabricated photomasks that do not allow on‐demand designs. Herein is reported on and characterization spatially patterned PDLC “pixels” using drop‐on‐demand inkjet printing, it...
Abstract Adaptive optics (AO) is a powerful tool employed across various research fields, from aerospace to microscopy. Traditionally, AO has focused on correcting optical phase aberrations, with recent advances extending polarisation compensation. However, intensity errors are also prevalent in systems, yet effective correction methods still their infancy. Here, we introduce novel approach, termed adaptive (I-AO), which employs dual-feedback loop mechanism first address non-uniform...
If a surface-modulated diffraction grating is arranged so that the scattering vector does not lie in plane of incidence illuminating radiation, then polarization conversion can occur. This be strongly enhanced if surface mode, such as surface-plasmon-polariton or guided excited at surface. In this paper we develop mathematical description process, using method transforms into planar system. The predicted compared very favorably with data for surface-mode-enhanced conversion.
Abstract Direct laser writing is demonstrated by two‐photon polymerization of multi‐element diffractive optical components that can be switched on and off with an applied voltage. By exploiting the 3D capabilities microfabrication technique, multiple elements are written into a single liquid crystal (LC) layer. The switching behavior controlled simply changing write‐voltage anisotropic polymer structures during fabrication. Initially, 2D diffraction gratings at different depths within LC...
Abstract Optical Skyrmions have many important properties that make them ideal units for high-density data applications, including the ability to carry digital information through a discrete topological number and independence of spatially varying polarization other dimensions. More importantly, nature optical Skyrmion heuristically suggests strong degree robustness perturbations, which is crucial reliably carrying in noisy environments. However, study still its infancy. Here, we quantify...
Abstract Topological defects are a consequence of broken symmetry in ordered systems and important for understanding wide variety phenomena physics. In liquid crystals (LCs), exist as points discontinuous order the vector field that describes average orientation molecules space crucial explaining fundamental behaviour properties these mesophases. Recently, LC have also been explored from perspective technological applications including self-assembly nanomaterials, optical-vortex generation...
The helical flexoelectro-optic effect produces a submillisecond, temperature-independent in-plane rotation of the optical axis and is potentially interesting for display industry. main drawback that it relies on texture, uniform lying helix (ULH), which intrinsically unstable. We present method based use periodic polymeric microchannels to create highly ordered stable ULH structures. Electro-optic measurements performed test device show large contrast ratio between bright dark states (better...
A large flexoelectric polarization might be expected for a bent-core nematic liquid crystal, due to the combination of molecular shape and transverse dipole component. In this study compound is doped highly chiral, measurements difference in coefficients $({e}_{1}\ensuremath{-}{e}_{3})$ are carried out by exploiting chiral flexoelectro-optic effect. The measured greater than those many conventional calamitic nematics, but several orders magnitude lower recent reports on other compounds....
Abstract Two‐photon laser writing is a powerful technique for creating intricate, high resolution features in polymerizable materials. Here, using single‐step process to microfabricate polymer inclusions, the ability generate read‐on‐demand images and identification codes liquid crystal (LC) device demonstrated. These micrometer‐sized are encoded directly into LC devices direct writing, which locks‐in local molecular orientation at moment of fabrication. By reading with same voltage...
We demonstrate laser writing of birefringent polymer structures with a controllable orientation the optic axis in liquid crystal devices.
Abstract By observing the angular dependence of reflectivity a ferroelectric liquid crystal (FLC) cell fabricated from glass pyramids with 60° evaporated SiO aligning layers it has been possible to sensitively probe configuration optical dielectric tensor in FLC layer. It is found that data can best be explained by uniaxial slab twisted alignment axis; this consistent recently proposed chevron structure.
Complete electronic and micro-mechanical systems can now be fabricated on the scale of hundreds microns. Implementing radio frequency wireless communications with such 'smart dust' is challenging, due to power required small size any antennas that implemented. Optical communications, using a modulated retro-reflector at smart dust has advantages low-power consumption highly directive channels allow long ranges. In this paper we report design implementation system uses base station...
The flexoelectro-optic effect in the uniform lying helix (ULH) geometry could provide many advantages over existing liquid-crystal technologies, however reliably forming ULH has been problematic. Here, we achieve spontaneous, stable, and repeatable alignment for materials with both positive negative dielectric anisotropy devices ranging from 1 to 7 μm thickness without need any field application or flow-induced alignment, using a combination of weak homeotropic conditions unidirectional...
In this paper, we investigate the potential of achieving polarization independent phase modulation using supertwisted nematic (STN) liquid crystal (LC) devices. Here, describe use a burst driving voltage applied to 180° STN LC device obtain twist symmetric H (T-Hs) state, which enables simultaneous light for all polarizations, demonstrating characteristic in time domain. Additionally, consider 90° twisted (TN) comparison, as can also exhibit characteristics. Simulations were carried out...