Ian R. Hooper
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View article: Quasi Normal Modes in Dispersive Photonic Time-Crystals
Quasi Normal Modes in Dispersive Photonic Time-Crystals Open
Quasinormal modes characterise the transient response of static optical cavities. Here, we introduce the notion of a Floquet quasinormal mode to describe transient responses in photonic time crystals. Contrasting their static counterparts,…
View article: The 2025 Active Metamaterials Roadmap
The 2025 Active Metamaterials Roadmap Open
Active metamaterials are engineered structures that possess novel properties that can be changed after the point of manufacture. Their novel properties arise predominantly from their physical structure, as opposed to their chemical composi…
View article: Harnessing the frequency eigenchannels of ultrafast time-varying media
Harnessing the frequency eigenchannels of ultrafast time-varying media Open
Control over the interaction of waves with ultrafast time-varying materials - those that change on a time-scale commensurate with the wave period - holds much promise for developing a raft of new technologies. Time-varying materials exchan…
View article: Hyperspectral imaging of microwave metasurfaces with deeply subwavelength resolution
Hyperspectral imaging of microwave metasurfaces with deeply subwavelength resolution Open
Electromagnetic metasurfaces offer a route to exotic, customised material properties that are not found in nature. However, in practice these artificial materials often do not live up to the promise of their design, limited by a myriad of …
View article: Symmetry-protected lossless modes in dispersive time-varying media
Symmetry-protected lossless modes in dispersive time-varying media Open
We give an exact application of a recently developed, operator-based theory of wave propagation in dispersive, time-varying media. Using this theory, we find that the usual symmetry of complex conjugation plus changing the sign of the freq…
View article: Method for extracting the surface impedance of a generic reflective metasurface
Method for extracting the surface impedance of a generic reflective metasurface Open
View article: The 2024 Active Metamaterials Roadmap
The 2024 Active Metamaterials Roadmap Open
Active metamaterials are engineered structures that possess novel properties that can be changed after the point of manufacture. Their novel properties arise predominantly from their physical structure, as opposed to their chemical composi…
View article: Symmetry-Protected Lossless Modes in Dispersive Time-Varying Media
Symmetry-Protected Lossless Modes in Dispersive Time-Varying Media Open
We give an exact application of a recently developed, operator-based theory of wave propagation in dispersive, time-varying media. Using this theory we find that the usual symmetry of complex conjugation plus changing the sign of the frequ…
View article: A Dual-Band Spaceplate: Contracting the Volume of Quasi-Optical Systems
A Dual-Band Spaceplate: Contracting the Volume of Quasi-Optical Systems Open
This is the author accepted manuscript. The final version is available from IEEE via the DOI in this record
View article: Terahertz imaging through emissivity control
Terahertz imaging through emissivity control Open
Electromagnetic radiation in the terahertz (THz) frequency band has unique potential for future communication and imaging applications. However, the adoption of THz technologies is hindered by the lack of cost-effective THz sources. Here w…
View article: Terahertz imaging through emissivity control
Terahertz imaging through emissivity control Open
Adoption of terahertz technologies is hindered by the lack of cost-effective THz sources. Here we demonstrate a fundamentally new way to generate and control THz radiation, via spatio-temporal emissivity modulation. By patterning the optic…
View article: Reconfigurable Elastic Metamaterials: Engineering Dispersion with Beyond Nearest Neighbors
Reconfigurable Elastic Metamaterials: Engineering Dispersion with Beyond Nearest Neighbors Open
This is the final version. Available on open access from the American Physical Society via the DOI in this record
View article: Multi-resonant tessellated anchor-based metasurfaces
Multi-resonant tessellated anchor-based metasurfaces Open
View article: Engineering the carrier lifetime and switching speed in Si-based mm-wave photomodulators
Engineering the carrier lifetime and switching speed in Si-based mm-wave photomodulators Open
For a diverse range of semiconductor devices, the charge carrier lifetime is an essential characteristic. However, the carrier lifetime is difficult to control, as it is usually determined by a variety of recombination processes. For indir…
View article: Multi-scale bullseye antennas
Multi-scale bullseye antennas Open
We design, simulate and experimentally characterize a multi-scale bullseye antenna for the broadband manipulation of microwaves. The device achieves far-field beam-forming via tailored diffraction at the interface between two concentric bu…
View article: Space squeezing optics: Performance limits and implementation at microwave frequencies
Space squeezing optics: Performance limits and implementation at microwave frequencies Open
Optical systems often largely consist of empty space as diffraction effects that occur through free-space propagation can be crucial for their function. Contracting these voids offers a path to the miniaturization of a wide range of optica…
View article: Effective-periodicity effects in Fibonacci slot arrays
Effective-periodicity effects in Fibonacci slot arrays Open
In this Letter, the transmission properties of a nonperiodic array of slots arranged in the form of a Fibonacci sequence are investigated. By arranging the slots in this manner, an additional periodicity can be utilized, resulting in corre…
View article: Exploring microwave absorption by non-periodic metasurfaces
Exploring microwave absorption by non-periodic metasurfaces Open
In recent years there has been a large body of work investigating periodic metasurface microwave absorbers. However, surprisingly few investigations have focused on the absorption performance of similar non-periodic designs. In this work, …
View article: Metamaterial Analogues of Strongly Coupled Molecular Ensembles
Metamaterial Analogues of Strongly Coupled Molecular Ensembles Open
The formation of polariton modes due to the strong coupling of light and matter has led to exciting developments in physics, chemistry, and materials science. The potential to modify the properties of molecular materials by strongly coupli…
View article: Absorption modes of Möbius strip resonators
Absorption modes of Möbius strip resonators Open
View article: Efficient mm-wave photomodulation via coupled Fabry–Perot cavities
Efficient mm-wave photomodulation via coupled Fabry–Perot cavities Open
An efficient mm-wave photomodulator is designed based on coupled Fabry–Perot modes in a low-lifetime silicon wafer and an adjacent cavity formed from a transparent reflector, such as indium tin oxide. The modulation of a reflected beam usi…
View article: Supplementary document for Total internal reflection based super-resolution imaging for sub-IR frequencies - 4982250.pdf
Supplementary document for Total internal reflection based super-resolution imaging for sub-IR frequencies - 4982250.pdf Open
Clean copy of the supplementary document
View article: Direct observation of defect modes in molecular aggregate analogs
Direct observation of defect modes in molecular aggregate analogs Open
This is the final version. Available from the American Physical Society via the DOI in this record
View article: Super-resolution imaging for sub-IR frequencies based on total internal reflection
Super-resolution imaging for sub-IR frequencies based on total internal reflection Open
For measurements designed to accurately determine layer thickness, there is a natural trade-off between sensitivity to optical thickness and lateral resolution due to the angular ray distribution required for a focused beam. We demonstrate…
View article: Direct observation of defect modes in molecular aggregate analogues (dataset)
Direct observation of defect modes in molecular aggregate analogues (dataset) Open
In this work we investigate defect modes localised at the ends and within the bulk of 1D metamaterial analogues of molecular aggregates. The study is undertaken in the microwave regime, where the cm scale of the metamaterial analogue provi…
View article: Total internal reflection based super-resolution imaging for sub-IR\n frequencies
Total internal reflection based super-resolution imaging for sub-IR\n frequencies Open
For measurements designed to accurately determine layer thickness, there is a\nnatural trade-off between sensitivity to optical thickness and lateral\nresolution due to the angular ray distribution required for a focused beam. We\ndemonstr…
View article: Total internal reflection based super-resolution imaging for sub-IR frequencies
Total internal reflection based super-resolution imaging for sub-IR frequencies Open
For measurements designed to accurately determine layer thickness, there is a natural trade-off between sensitivity to optical thickness and lateral resolution due to the angular ray distribution required for a focused beam. We demonstrate…
View article: Millimetre-wave total internal reflection based computational imaging
Millimetre-wave total internal reflection based computational imaging Open
Imaging at millimetre wavelengths offers a promising route to the mapping of material properties in biological tissue. However, mm-wave radiation is difficult to control and detect, and the long wavelengths typically limit spatial resoluti…
View article: High efficiency photomodulators for millimeter wave and THz radiation
High efficiency photomodulators for millimeter wave and THz radiation Open
View article: Metamaterial Analogues of Molecular Aggregates
Metamaterial Analogues of Molecular Aggregates Open
Molecular aggregates are a fascinating and important class of materials, particularly in the context of optical (pigmented) materials. In nature, molecular aggregates are employed in photosynthetic light harvesting structures, while synthe…