1,725,924 research outputs found
Dataset for the journal article 'Photonic Metamaterial Analogue of a Continuous Time Crystal'
No full textExperimental data presented in the paper published in Nature Physics:
Photonic metamaterial analogue of a continuous time crystal, Tongjun Liu, Jun-Yu. Ou, Kevin F. MacDonald, Nikolay I. Zheludev, Nat. Phys.
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Random access actuation of nanowire grid metamaterial
Full text linkDataset supporting:
Cencillo Abad, Pablo, Ou, Jun-Yu, Plum, Eric, Valente, João and Zheludev, Nikolay (2016) Random access actuation of nanowire grid metamaterial. Nanotechnology, 27, 485206</span
Dataset for Visualization of Sub-atomic Movements in Nanostructures
No full textExperimental data presented in the paper published in Nano Letters:
Tongjun Liu, Jun-Yu Ou, Eric Plum, Kevin F. MacDonald, and Nikolay I. Zheludev (2021), 'Visualization of Subatomic Movements in Nanostructures', NANO Letters,
https://doi.org/10.1021/acs.nanolett.1c02644</span
Coherent selection of invisible high-order electromagnetic excitations
Full text linkResearch data for Coherent selection of invisible high-order electromagnetic excitations, Ming Lun Tseng, Xu Fang, Vassili Savinov, Pin Chieh Wu, Jun-Yu Ou, Nikolay I. Zheludev, and Din Ping Tsai, Scientific Reports 7, 44488(2017)</span
Captive breeding of orchid dottyback Pseudochromis fridmani: reproduction, ontogeny and larval feeding regime
No full textJun Yu Chen investigated the captive breeding of orchid dottyback. He documented the reproductive biology and early ontogeny of orchid dottyback in captivity, and established effective larval rearing techniques for this species. His results can be applied to cost-effectively produce orchid dottyback to supply the marine ornamental fish trade
Method for optimising the performance of PML in anchor-loss limited model via COMSOL
No full textPerfectly matched layer has been used for solving anchor-loss limited quality factor in the Micro electromechanical systems. However, setting up a well-behaved perfectly matched layer requires users to change the parameters of a perfectly matched layer to give correct results, while the current existing methods for choosing the right parameters are vague and lack theoretical support. Based on the mathematical theory of perfectly matched layer and simulation results of a beam structure's quality factor, this paper proposes a method for choosing the parameter to optimise the performance of perfectly matched layer in COMSOL. The accuracy of the proposed method is proved by matching the effect of substrate height on beam's quality factor with theory prediction. The author also studies the effect of beam height and beam width on the quality factor of the beam. The results demonstrate that simulated quality factors are in agreement with analytical values when the ratio of height over length is small but will show great divergence when height equals the length. This trend can be observed for the beam width as well. Especially for larger ratio of beam width over beam length, instead of decreasing monotonously as analytical equitation would expect, the simulated quality factor will converge into a stable value of 1700, which matches the result of two-dimensional model for the same beam structure. This means that a three-dimensional model has to be used for estimating the quality factor of a beam structure
Reconfigurable photonic metamaterials
No full textThis thesis reports on the development of a new class of switchable nanostructured photonic metamaterials, Reconfigurable Photonic Metamaterials (RPMs). Over the last decade, fascinating material properties including negative refraction, optical magnetism, invisibility, asymmetric transmission, perfect lenses and many more were demonstrated in metamaterials. Inspired by pioneering work on micro-electro mechanical metamaterials for the terahertz and microwave spectral regions with feature sizes from millimeters to tens and hundreds microns, I develop reconfigurable photonic metamaterials for the optical spectral range that have sub-micron meta molecules and nanoscale design features.In particular, for the first time I developed: Novel fabrication processes for manufacturing reconfigurable photonic metamaterials based on the platform of elastic silicon nitride membranes using focused ion beam lithography, film deposition, precise alignment, etching and annealing techniques. These fabrication techniques have allowed the manufacturing of a wide range of reconfigurable metamaterials consisting of bi-layer (gold/silicon nitride) or tri-layer (gold/silicon nitride/gold) structured membranes suitable for applications as plasmonic RPMs.Novel RPMs tunable by ambient temperature that operate in the optical and near infrared parts of the spectrum. With such metamaterials exploiting the change in plasmonic response due to differential thermal expansion in bimorph nanostructures I have demonstrated 50% changes in optical transmission at the wavelength of 1735 nm when the temperature is ramped from 76 K to 270 K.Novel RPMs operating in the near-infrared part of the spectrum that can be controlled by electric signals. These types of metamaterials harness electrostatic forces on the nanoscale and offer up to 20 MHz modulation bandwidth. At a threshold level of stimulation these metamaterials exhibit non-volatile switching with up to 250% transmission change. As a part of this research I developed a characterization technique that allows imaging and recording of the electrostatic switching under a scanning electron microscope.Novel optically controlled RPMs exploiting near-field optical forces induced by light and optical heating for reconfiguration. Such metamaterials show a new type of optomechanical nonlinearity leading to intensity-dependent transmission that exceeds the cubic nonlinearity of GaAs by seven orders of magnitude. Using CW diode lasers operating at telecommunication wavelengths of 1.3 µm and 1.55 µm I have demonstrated cross-wavelength optical modulation with amplitude of about 1 % that can be achieved at only about 1 mW of average power of the control beam. I also developed the numerical analysis of thermo-opto-mechanical properties of the structures and calculated eigenmodes and cooling constants of the RPMs under modulated laser irradiation.Overall, the development of reconfigurable photonic metamaterials provides a new and flexible platform for the control of metamaterial properties "on demand". Such metamaterials can find applications in sensors, tunable spectral filters, switches, modulators, programmable transformation optics devices and any other application where tunable optical properties are required
Dataset supporting an article "Picophotonics localization metrology beyond thermal fluctuations".
No full textThis dataset supports the publication: Picophotonic localization metrology beyond thermal fluctuations by Cheng-Hung Chi, Tongjun Liu, Jun-Yu Ou, Jie Xu, Eng Aik Chan, Kevin F. MacDonald, and Nikolay I. Zheludev
in JOURNAL: Nature Materials
The data file contains the as-recorded (unprocessed, uncropped, etc.) image files from which Fig. 2 and Fig. S1c are derived. [Figure 1 is a schematic graphic; Figure 3 shows the results of computational modelling, all details of which are contained within the manuscript]. Fig. 2. Optical measurements of nanowire displacement. a,b, Optically measured versus actual values of nanowire displacement for plane-wave (a) and topologically structured
super oscillatory (b) illumination. Fig. S1. Fig. S1. Nanowire position calibration. (a) SEM image of the entire nanowire sample, showing the electrode configuration for electrostatic cont rol of [ x direction] position; (b) representative pair of high magnification images of the ( y direction) midpoint of the nanowire from which the dependence of nanowire displacement on applied bias panel (c) is derived. [Error bars in (c) denote the unc ertainty associated with a 1 pixel error in determining the nanowire edge position from SEM images.
The project was sponsored by:
Next Generation Metrology Driven by Nanophotonics
EPSRC EP/T02643X/1
Dataset available under a CC BY 4.0 licence</span
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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