| 1. |
- Hao, Jiaming, et al.
(författare)
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Ultrathin wide-angle optical metamaterial absorber
- 2010
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Ingår i: Optical Nanostructures for Photovoltaics, PV 2010. - Washington, D.C. : Optical Society of America (OSA). - 9781557528964
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Konferensbidrag (refereegranskat)abstract
- We present design, analysis, and experimental demonstration of an ultra-thin, wide-angle perfect metamaterial absorber at optical frequency. The absorption is tunable by adjusting the nanostructure dimensions and is almost independent of the incidence angle.
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| 2. |
- Chen, Xi, et al.
(författare)
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Nanosecond Photothermal Effects in Plasmonic Nanostructures
- 2012
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 6:3, s. 2550-2557
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Tidskriftsartikel (refereegranskat)abstract
- Photothermal effects in plasmonic nanostructures have great potentials in applications for photothermal cancer therapy, optical storage, thermo-photovoltaics, etc. However, the transient temperature behavior of a nanoscale material system during an ultrafast photothermal process has rarely been accurately investigated. Here a heat transfer model is constructed to investigate the temporal and spatial variation of temperature in plasmonic gold nanostructures. First, as a benchmark scenario, we study the light-induced heating of a gold nanosphere in water and calculate the relaxation time of the nanosphere excited by a modulated light. Second, we investigate heating and reshaping of gold nanoparticles in a more complex metamaterial absorber structure induced by a nanosecond pulsed light. The model shows that the temperature of the gold nanoparticles can be raised from room temperature to >795 K in just a few nanoseconds with a low light luminance, owing to enhanced light absorption through strong plasmonic resonance. Such quantitative predication of temperature change, which Is otherwise formidable to measure experimentally, can serve as an excellent guideline for designing devices for ultrafast photothermal applications.
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| 3. |
- Zhao, Ding, et al.
(författare)
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Ultra-narrow-band light dissipation by a stack of lamellar silver and alumina
- 2014
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 104:22
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Tidskriftsartikel (refereegranskat)abstract
- An ultra-narrow band absorber consisting of continuous silver and alumina films is investigated. Owing to Fabry–Pérot resonance and silver's inherent loss, an ultra-narrow spectral range of light can be entirely trapped in the structure. By varying thicknesses of metallic and dielectric films, absorption peak shifts in visible and near-infrared regions. When two such metal-insulator-metal stacks are cascaded, experimental results show that an ultra-narrow absorption bandwidth of 7 nm is achieved, though theoretical results give that of 2 nm. Features of high-efficiency and ultra-narrow band absorption have huge potential in optical filtering, thermal emitter design, etc.
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| 4. |
- Benisty, H., et al.
(författare)
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Low-loss photonic-crystal and monolithic InP integration : Bands, bends, lasers, filters
- 2004
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Ingår i: Photonic Crystal Materials and Devices II. - : SPIE - International Society for Optical Engineering. - 0819452688 ; , s. 119-128
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Konferensbidrag (refereegranskat)abstract
- Practical realizations of 2D (planar) photonics crystal (PhC) are either on a membrane or etched through a conventional heterostructure. While fascinating objects can emerge from the first approach, only the latter approach lends itself to a progressive integration of more compact PhC's towards monolithic PICs based on InP. We describe in this talk the various aspects from technology to functions and devices, as emerged from the European collaboration "PCIC". The main technology tour de force is deep-etching with aspect ratio of about 10 and vertical sidewall, achieved by three techniques (CAIBE, ICP-RIE, ECR-RIE). The basic functions explored are bends, splitters/combiners, mirrors, tapers, and the devices are filters and lasers. At the end of the talk, I will emphasize some positive aspects of "broad" multimode PhC waveguides, in view of compact add-drop filtering action, notably.
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| 5. |
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| 6. |
- Chen, Xi, et al.
(författare)
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Photothermal phenomena in plasmonics and metamaterials
- 2011
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Ingår i: ADVANCES IN OPTICAL THIN FILMS IV. - : SPIE. - 9780819487940 ; , s. 81681K-
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Konferensbidrag (refereegranskat)abstract
- Our recent theoretical and experimental investigation of the photothermal effect in a planar metamaterial absorber is reviewed in the present paper. The observed ultrasensitive photothermal heating in such an absorber nanostructure irradiated by a pulsed white-light source is elaborated with a simple yet compelling heat transfer model, which is subsequently solved with a finite-element method. The simulation results not only agree with the experimental finding, but also provide more detailed understanding of the temperature transition in the complex system.
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| 7. |
- Chen, Xi, et al.
(författare)
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Photothermally tunable silicon-microring-based optical add-drop filter through integrated light absorber
- 2014
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Ingår i: Optics Express. - 1094-4087. ; 22:21, s. 25233-25241
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Tidskriftsartikel (refereegranskat)abstract
- An optically pumped thermo-optic (TO) silicon ring add-drop filter with fast thermal response is experimentally demonstrated. We propose that metal-insulator-metal (MIM) light absorber can be integrated into silicon TO devices, acting as a localized heat source which can be activated remotely by a pump beam. The MIM absorber design introduces less thermal capacity to the device, compared to conventional electrically-driven approaches. Experimentally, the absorber-integrated add-drop filter shows an optical response time of 13.7 mu s following the 10%-90% rule (equivalent to a exponential time constant of 5 mu s) and a wavelength shift over pump power of 60 pm/mW. The photothermally tunable add-drop filter may provide new perspectives for all-optical routing and switching in integrated Si photonic circuits.
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| 8. |
- Dai, Jin, et al.
(författare)
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Light absorber based on nano-spheres on a substrate reflector
- 2013
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Ingår i: Optics Express. - 1094-4087. ; 21:6, s. 6697-6706
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Tidskriftsartikel (refereegranskat)abstract
- We systematically study a type of plasmonic light absorber based on a monolayer of gold nano-spheres with less than 30 nm in diameters deposited on top of a continuous gold substrate. The influences of particle size, inter-particle distance, particle-substrate spacer size etc on the resonance are studied thoroughly with a 3D finite-element method. We identified that the high-absorption resonance is mainly due to gap plasmon (coupled through particle bodies) when the separation between neighboring nano-spheres is small enough, such as close to 1 nm; at larger particle separations, the resonance is dominated by particle dipoles (coupled through the host dielectric). Experimentally, an absorber was fabricated based on chemically-synthesized gold nanoparticles coated with silica shell. The absorber shows a characteristic absorption band around 810 nm with a maximum absorbance of approximately 90%, which agrees reasonably well with our numerical calculation. The fabrication technique can be easily adapted for devising efficient light absorbers of large areas.
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| 9. |
- Ding, Boyang, et al.
(författare)
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Manipulating light absorption in dye-doped dielectric films on reflecting surfaces
- 2014
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Ingår i: Optics Express. - 1094-4087. ; 22:21, s. 25965-25975
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Tidskriftsartikel (refereegranskat)abstract
- We experimentally and numerically developed a tunable absorbing nanoscale thin-film system, comprising of dye molecules doped dielectric coatings on reflecting surfaces, the absorption behaviors of which can be flexibly tuned by adjusting the system parameters, i.e. the coating thickness and the doping concentration of dye molecules. Specifically, with appropriate system parameters, our absorbing thin-film system exhibits very directional and polarization dependent absorption properties, which can be significantly altered if applied with different parameters. Calculations demonstrate the unique absorption behaviors are a result of coupling between molecular absorption and Fabry-Perot resonances in the thin-film cavity. In addition, we theoretically show that both the spectral and directional range of the absorption in the thin-film system can be intentionally regulated by doping dyes with different absorption band and setting proper excitation conditions of Fabry-Perot resonances.
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| 10. |
- Fu, Ying, et al.
(författare)
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Optical properties of nanostructures
- 2011
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Nanotechnology has been named as one of the most important areas of forthcoming technology because it promises to form the basis of future generations of electronic and optoelectronic devices. From the point of view of technical physics, all these developments greatly reduce the geometric sizes of devices, and thus the number of active electrons in the system. Quantum mechanical considerations about electronic states, electron transports, and various scattering processes, including light-matter interaction, are thus crucial. However, the theoretical study is extremely difficult. The authors' first numerical simulation work about a three-dimensional energy band structure calculation in 1995 took more than 6 months to complete for one bias configuration of a nanoscale metal-oxide-semiconductor field-effect transistor. With today's computation workstations the CPU time is reduced to less than 24 hours. This book discusses electrons and photons in and through nanostructures by the first-principles quantum mechanical theories and fundamental concepts (a unified coverage of nanostructured electronic and optical components) behind nanoelectronics and optoelectronics, the material basis, physical phenomena, device physics, as well as designs and applications. The combination of viewpoints presented in the book can help foster further research and cross-disciplinary interaction needed to surmount the barriers facing future generations of technology design.
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