A5029399403- Photonic and Optical Devices
- Photonic Crystals and Applications
- Optical Coatings and Gratings
- Nanowire Synthesis and Applications
- Semiconductor Lasers and Optical Devices
- Semiconductor materials and devices
- Silicon Nanostructures and Photoluminescence
- Graphene research and applications
- ZnO doping and properties
- Advancements in Semiconductor Devices and Circuit Design
- Thin-Film Transistor Technologies
- Gas Sensing Nanomaterials and Sensors
- Mechanical and Optical Resonators
- Analytical Chemistry and Sensors
- Advanced MEMS and NEMS Technologies
- Advanced Fiber Laser Technologies
- Force Microscopy Techniques and Applications
- Quantum and electron transport phenomena
- Photorefractive and Nonlinear Optics
- GaN-based semiconductor devices and materials
- Plasmonic and Surface Plasmon Research
- Advanced Memory and Neural Computing
- Diamond and Carbon-based Materials Research
- Advanced Surface Polishing Techniques
- Spectroscopy Techniques in Biomedical and Chemical Research
University of Southampton
2016-2025
Japan Advanced Institute of Science and Technology
2019-2022
University of Bristol
2022
Lancaster University
2022
Bronx High School of Science
2017
University at Albany, State University of New York
2013
University of Surrey
2012
University of Glasgow
1999-2009
University of Liège
2008
Institute of Electronics
2005
We demonstrate a novel polarization splitter based on two-dimensional grating etched in silicon-on-insulator waveguide. The device couples orthogonal modes from single-mode optical fiber into identical of two planar ridge waveguides. extinction ratio is better than 18 dB the wavelength range 1530-1560 nm and coupling efficiency approximately 20%. very compact light only to transverse-electric Therefore, it may be used diversity configuration implement insensitive photonic integrated circuit crystal
Due to its excellent electronic and photonic properties, silicon is a good candidate for mid-infrared optoelectronic devices systems that can be used in host of applications.In this paper we review some the results reported recently, also present several new on midinfrared including Mach-Zehnder interferometers, multimode interference splitters multiplexers based silicon-oninsulator, polysilicon, suspended silicon, slot waveguide platforms.
Germanium based photonic devices can play a significant role in several applications, particularly the so-called fingerprint wavelength region. Here, we review our recent results on mid-infrared germanium that show promising performance 2-7.5 μm range.
Planar photonic crystal waveguide structures have been modelled using the finite-difference-time-domain method and perfectly matched layers employed as boundary conditions. Comprehensive numerical calculations performed compared to experimentally obtained transmission spectra for various waveguides. It is found that within experimental fabrication tolerances correctly predict measured levels other major features.
The realisation of a thermo-optically controlled symmetric Mach- Zehnder interferometer switch based on an AlGaAs/GaAs epitaxial waveguide structure operating at wavelengths in the region lambda = 1550 nm is reported. device very compact two-dimensional photonic crystal channel structure. measured and simulated transmission spectra for devices are good agreement. Pi-phase shift switching power as low 42 mW.
We report on the design, fabrication, and characterization of silicon-on-insulator rib strip waveguides at wavelengths longer than 3.7 μm. Propagation losses 1.5 ± 0.2 dB/cm 3.73 μm 1.8 3.8 have been measured for waveguides, whilst submicron exhibited propagation 4.6 1.1 wavelength 3.74 A 1×2 multimode interference (MMI) splitter racetrack resonators based are also examined. Optical 3.6 dB/MMI a resonator Q-value 8.2 k obtained
The direct growth of graphene on insulating substrate is highly desirable for the commercial scale integration due to potential lower cost and better process control. We report a simple, deposition nanocrystalline (NCG) substrates via catalyst-free plasma-enhanced chemical vapor at relatively low temperature ∼800 °C. parametric study conditions that we conducted reveals mechanism allows us grow high quality films. Based such film, demonstrate fabrication large-scale array...
The fabrication and characterisation of high-quality silicon membrane photonic crystals are reported. etching process was carefully optimised to give holes with very smooth vertical sidewalls, resulting in propagation, a minimum loss 4.1±0.9 dB/cm single line defect (W1) waveguide.
A tunable photonic crystal microcavity with in-filling holes has been experimentally realized by using the thermooptic effect in silicon-on-insulator waveguide at /spl lambda/=1530 nm. The device was fabricated reactive ion etching through silicon core layer for high vertical confinement. thin film heater integrated onto microcavity. small change temperature (and consequent refractive index) sufficient to cause an observable resonance shift. shift of 5 nm achieved when switched on a current...
We report an accurate scattering loss 3-D modeling technique of sidewall roughness optical SOI waveguides based on Fourier and finite-difference time domain (FDTD) analysis methods. The method is the image recovery used in magnetic resonant imaging. Losses for with isotropic anisotropic are calculated wavelengths ranging from 1550 to 3800 nm compared reported results literature. Our simulations show excellent agreement published experimental provide prediction roughness-induced arbitrary...
We report on multicolor excitation experiments with color centers in hexagonal boron nitride at cryogenic temperatures. demonstrate controllable optical switching between bright and dark states of emitting around 2eV. Resonant, or quasi-resonant also pumps the center, via a two-photon process, into state, where it becomes trapped. Photoluminescence spectroscopy reveals defect dependent energy threshold for repumping center state 2.2 2.6eV. Photoionization photocharging is most plausible...
Emerging applications such as the Internet-of-Things and more-electric aircraft require electronics with integrated data storage that can operate in extreme temperatures high energy efficiency. As transistor leakage current increases temperature, nanoelectromechanical relays have emerged a promising alternative. However, reliable scalable non-volatile relay retains its state when powered off has not been demonstrated. Part of challenge is electromechanical pull-in instability, causing beam...
The field of silicon photonics has experienced widespread adoption in the datacoms industry over past decade, with a plethora other applications emerging more recently such as light detection and ranging (LIDAR), sensing, quantum photonics, programmable artificial intelligence. As result this, many commercial complementary metal oxide semiconductor (CMOS) foundries have developed open access process lines, enabling mass production systems. On side spectrum, several research labs, typically...
This paper reports on large area, metal-free deposition of nanocrystalline graphene (NCG) directly onto wet thermally oxidized 150 mm silicon substrates using parallel-plate plasma-enhanced chemical vapor deposition.Thickness nonuniformities as low 13% are achieved over the whole substrate.The cluster size L a as-obtained films is determined from Raman spectra and lies between 1.74 2.67 nm.The film uniformity was further confirmed by mapping.The sheet resistance R sq 3.73 Ω k charge carrier...
Protein sensing in biological fluids provides important information to diagnose many clinically relevant diseases. Mid-infrared (MIR) absorption spectroscopy of bovine serum albumin (BSA) is experimentally demonstrated on a germanium silicon (GOS) waveguide the 1900–1000 cm–1 (5.3–10.0 μm) region MIR. GOS waveguides were shown guide light up wavelength 12.9 μm. The spectrum water, showing molecular bending vibrations, was obtained and compared with theoretical model good agreement....
We present the design, fabrication, and characterization of a microcavity that exhibits simultaneously high transmission large resonance quality-factor (Q-factor). This is formed by single-row photonic crystal (PhC) embedded in 500-nm-wide wire waveguide - based on silicon-on-insulator. A normalized 85%, together with Q-factor 18 500, have been achieved experimentally through use carefully designed tapering both sides each hole-type PhC mirrors form microcavity. also demonstrated reasonably...
This paper reports on a novel MEMS resonant sensing device consisting of three weakly coupled resonators that can achieve an order magnitude improvement in sensitivity to stiffness change, compared current state-of-the-art resonator sensors with similar size and frequency. In 3 degree-of-freedom (DoF) system, if external stimulus causes change the spring one resonator, mode localization occurs, leading drastic shape, which be detected by measuring modal amplitude ratio change. A 49 times...
Bolometers are thermal detectors widely applied in the mid-infrared (MIR) wavelength range. In an integrated sensing system on chip, a broadband scalable bolometer absorbing light over whole MIR range could play important role. this work, we have developed waveguide-based operating of 3.72–3.88 µm amorphous silicon (a-Si) platform. Significant improvements design result <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mn>20</mml:mn> <mml:mo>×</mml:mo>...
Abstract This study aims to exploit the resistance states of Cr/ZnO/TiN memristors generate random numbers. A number generator (RNG) circuit employing a single memristor is proposed. We suggest that current compliance (CC) significant parameter in determining quality randomness; it found low CCs (20‐50 µA) have wide state distribution facilitates bits. work provides insight into implementation for data security applications.
We present here a study of the combined nonlinear response plasmonic antenna—transparent conducting oxide hybrids for activation metamaterial devices. Nanoantenna layers consisting randomly positioned gold nanodisk dimers are fabricated using hole-mask lithography. The nanoantenna covered with 20 nm thin layer transparent (TCO). investigate atomic deposited aluminum-doped zinc (AZO) next to indium–tin (ITO) produced sputter coating. show that our results in agreement hypothesis fast...