A5102939202- Metamaterials and Metasurfaces Applications
- Phase-change materials and chalcogenides
- Plasmonic and Surface Plasmon Research
- Photonic and Optical Devices
- Optical Coatings and Gratings
- Optical and Acousto-Optic Technologies
- Optical Polarization and Ellipsometry
- Chalcogenide Semiconductor Thin Films
- Photoacoustic and Ultrasonic Imaging
- Electromagnetic Compatibility and Measurements
- Electromagnetic Launch and Propulsion Technology
- Liquid Crystal Research Advancements
- Image Enhancement Techniques
- Thermal Radiation and Cooling Technologies
- Optical Imaging and Spectroscopy Techniques
- Advanced Fiber Optic Sensors
- Advanced SAR Imaging Techniques
- Gas Sensing Nanomaterials and Sensors
- Random lasers and scattering media
- Transition Metal Oxide Nanomaterials
- Orbital Angular Momentum in Optics
- Optical Coherence Tomography Applications
- Photonic Crystals and Applications
- Advanced Antenna and Metasurface Technologies
- Advanced Optical Imaging Technologies
University of Exeter
2025
University of Cambridge
2015-2024
Cancer Research UK Cambridge Center
2021
Cancer Research UK
2019
University of Strathclyde
2019
Texas Instruments (United States)
1973-1985
Sandia National Laboratories California
1963-1970
United States Department of Veterans Affairs
1969
Sandia Research (United States)
1963
Miniaturizing spectrometers Spectroscopy is a ubiquitous characterization tool spanning most scientific and many industrial disciplines. Most handheld are based on tabletop optical components, which limits the scale to these can be shrunk. To address desire for miniaturized with micrometer-scale (and smaller) footprint, Yang et al. developed such microspectrometer single, compositionally engineered nanowire. This result practical step forward use of other light-sensitive nanomaterials...
Significance In this work, we demonstrate a multicolor hologram based on plasmonic scattering of nanoparticles that is capable encoding more information than the spatial bandwidth dictates. This device designed fundamental concept diffraction produced by arrays nanoparticles. Hence, when multiple are multiplexed without coupling, they carry independent such as polarization and wavelength to far field. The shown unique because, our knowledge, first multichannel diffractive element from single...
Tunable narrowband spectral filtering across arbitrary optical wavebands is highly desirable in a plethora of applications, from chemical sensing and hyperspectral imaging to infrared astronomy. Yet, the ability reconfigure properties, with full reversibility, solid-state large-area filter remains elusive. Existing solutions require either moving parts, have slow response times, or provide limited coverage. Here, we demonstrate 1-inch diameter continuously tunable, fully reversible,...
Abstract Recent growth in space systems has seen increasing capabilities packed into smaller and lighter Earth observation deep mission spacecraft. Phase-change materials (PCMs) are nonvolatile, reconfigurable, fast-switching, have recently shown a high degree of radiation tolerance, thereby making them an attractive platform for spaceborne photonics applications. They promise robust, lightweight, energy-efficient reconfigurable optical whose functions can be dynamically defined on-demand...
The response of an antenna to dc pulse excitation, both in reception and transmission, can be determined by use Fourier transforms provided the complex impedance effective height are known over frequency range where excitation has significant components. We have computed time history a wide-angle conical show results herein for matched source transmission load several values cone angle length. Under conditions, faithful shape, requires long while is not possible. Faithful achieved short with...
We demonstrate spectrally-tunable Fabry-Perot bandpass filters operating across the MWIR by utilizing phase-change material GeSbTe (GST) as a tunable cavity medium between two (Ge:Si) distributed Bragg reflectors. The induced refractive index modulation of GST increases cavity’s optical path length, red-shifting passband. Our have spectral-tunability ∼300 nm, transmission efficiencies 60-75% and narrowband FWHMs 50-65 nm (Q-factor ∼70-90). further show multispectral thermal imaging gas...
In this paper, we propose a deep learning approach for forward modeling and inverse design of photonic devices containing embedded active metasurface structures. particular, demonstrate that combining neural network metasurfaces with scattering matrix-based optimization significantly simplifies the computational overhead while facilitating accurate objective-driven design. As an example, apply our to continuously tunable bandpass filter in mid-wave infrared, featuring narrow passband (∼10...
We have computed the response of a thin, cylindrical monopole antenna to dc pulse excitation, both in transmission and reception, by use Fourier transforms complex impedance effective height, for pulses space length ranging from two tenths twice length. also experimentally determined reponse obtained similar results. conclude this comparison that present steady-state theory together with methods will yield reliable results calculating antennas pulses. made certain other measurements step...
Conventional cameras, such as in smartphones, capture wideband red, green and blue (RGB) spectral components, replicating human vision. Multispectral imaging (MSI) captures spatial information beyond our vision but typically requires bulky optical components is expensive. Snapshot multispectral image sensors have been proposed a key enabler for plethora of MSI applications, from diagnostic medical to remote sensing. To achieve low-cost compact designs, spatially variant filter arrays (MSFAs)...
Abstract Mid‐infrared (MIR) spectroscopy is widely applied in many applications such as gas sensing, industrial inspection, astronomy, and imaging. While thin‐film narrowband interference filters are cost‐effective for MIR their complex fabrication limits suitability miniaturized systems. Plasmonic nanostructures, though explored applications, suffer from broad spectral responses low efficiencies due to the ohmic losses inherent metals. All‐dielectric metasurfaces, with intrinsic losses,...
Abstract Color filter arrays play a vital role in spectrally discriminating light into red, green and blue (RGB) bands—widely utilised color cameras display technology. Existing absorptive dye filters exhibit low transmission efficiencies require thicknesses several times that of the lateral pixel sizes they cover order to achieve sufficient spectral discrimination (leading cross-talk). Structural generation based on metasurfaces may alleviate challenges dye-based counterparts, due potential...
Phase and polarization of coherent light are highly perturbed by interaction with microstructural changes in premalignant tissue, holding promise for label-free detection early tumors endoscopically accessible tissues such as the gastrointestinal tract. Flexible optical multicore fiber (MCF) bundles used conventional diagnostic endoscopy endomicroscopy scramble phase polarization, restricting clinicians instead to low-contrast amplitude-only imaging. We apply a transmission matrix...
Abstract The growing demand for multifunctional nanophotonic devices has led to the exploration, and utilization, of a plethora exotic electro-optical materials. Recently, chalcogenide glass based phase change materials (PCMs) have shown utility as tuning material range devices. Owing their low loss, ultrafast switching speeds wide waveband operation, PCMs are integrated in an increasing number next-generation tunable components, including photonic switches, metasurface optics spectral...
Plasmonic pixels have been shown to offer numerous advantages over pigment-based color filters used in modern commercial liquid crystal (LC) displays. However, wideband dynamic tunability across the visible spectrum remains challenging. We experimentally demonstrate transmissive electrically tunable LC-nanohole operating with unpolarized input light. An ultrathin Al nanohole electrode is designed exhibit a polarized spectral response based on surface plasmon resonances. output analyzer...
A single-step fabrication method is presented for ultra-thin, linearly variable optical bandpass filters (LVBFs) based on a metal-insulator-metal arrangement using modified evaporation deposition techniques. This alternate process methodology offers reduced complexity and cost in comparison to conventional techniques fabricating LVBFs. We are able achieve linear variation of insulator thickness across sample, by adjusting the geometrical parameters typical physical vapor process. demonstrate...
The ability to form images through hair-thin optical fibres promises open up new applications from biomedical imaging industrial inspection. Unfortunately, deployment has been limited because small changes in mechanical deformation (e.g. bending) and temperature can completely scramble information, distorting images. Since such are dynamic, correcting them requires measurement of the fibre transmission matrix (TM) situ immediately before imaging. TM calibration typically access both proximal...
Multispectral imaging captures spatial information across a set of discrete spectral channels and is widely utilized diverse applications such as remote sensing, industrial inspection, biomedical imaging. filter arrays (MSFAs) are mosaics integrated atop image sensors that facilitate cost-effective, compact, snapshot multispectral MSFAs pre-configured based on application-where selected corresponding to targeted absorption spectra-making the design optimal vital for given application....
Abstract A new type of metalens with the capability to selectively focus narrowband light is reported at different focal planes depending on polarization. Two zone two lengths are spatially multiplexed and encoded in subwavelength regime arrays orthogonal silver nanostructures, which designed exhibit strong wavelength‐ polarization‐dependent scattering profiles. Using this principle, imaging under white‐light illumination independent experimentally demonstrated for each polarization resonant...
State-of-the-art pixels for high-resolution microdisplays utilize reflective surfaces on top of electrical backplanes. Each pixel is a single fixed color and will usually only modulate the amplitude light. With rise nanophotonics, pixel's relatively large surface area (~10 μm
Abstract Miniaturization down to the nanoscale has enabled a new paradigm of ultrathin optical devices, capable manipulating direction, polarization, and frequency light. Great interest is drawn by promising prospects deep‐subwavelength material dimensions. However, interesting properties opportunities offered structures with sizes comparable wavelength light appear have been overlooked. Here, quasiplanar chiral arrays made gold are considered show that higher‐order diffracted beams can...
Flexible optical fibres, used in conventional medical endoscopy and industrial inspection, scramble phase polarisation information, restricting users to amplitude-only imaging.Here, we exploit the near-diagonality of multi-core fibre (MCF) transmission matrix a parallelised characterisation architecture, enabling accurate imaging quantitative (error <0.3 rad) polarisation-resolved (errors <10%) properties.We first demonstrate recovery amplitude two polarisations through MCF by measuring...
Photograph of the experimental setup with light diffracting from a racemic nanoarray. The diffracted spectra change depending on direction circularly polarized illumination.
The study of the homing instinct migratory birds, that mysterious and still unexplained ability which unerringly guides avian travelers, sometimes through darkness, fog, storm, is intriguing also important in practical management. inclination birds to travel ancestral flyways return same nesting or wintering ground has long been known recent times amply demonstrated records from banded (Lincoln, 1935). regularity such movements, particularly during spring migrations, time again individuals...