| 1. |
- Cui, Yanxia, et al.
(författare)
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Exciting multiple plasmonic resonances by a double-layered metallic nanostructure
- 2011
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Ingår i: Journal of the Optical Society of America. B, Optical physics. - 0740-3224 .- 1520-8540. ; 28:11, s. 2827-2832
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Tidskriftsartikel (refereegranskat)abstract
- By placing a metallic layer of a periodic nanostrip array above a metallic layer of a periodic nanogroove array with a separation of 120nm, we obtain a triple-band thin film absorber with all its resonant wavelengths displaying absorptivity greater than 90%. Through a systematic study of the current compound structure, we find these three absorption peaks mainly depend on some simple resonances, i.e., the modes supported by the nanostrip array in the top layer, the nanogroove array in the bottom layer, and the horizontal cavity between the two layers. In addition, we show that this kind of absorber is quite robust and fairly insusceptible to the parallel shift between the two different layers. This study should contribute to the design of thin film absorbers/ emitters.
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| 2. |
- Cui, Yanxia, et al.
(författare)
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Plasmon-Assisted Optical Curtains
- 2010
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Ingår i: PLASMONICS. - : Springer Nature. - 1557-1955 .- 1557-1963. ; 5:4, s. 369-374
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Tidskriftsartikel (refereegranskat)abstract
- We predict an optical curtain effect, i.e., formation of a spatially invariant light field as light emerges from a set of periodic metallic nano-objects. The underlying physical mechanism of generation of this unique optical curtain can be explained in both the spatial domain and the wave-vector domain. In particular, in each period, we use one metallic nanostrip to equate the amplitudes of lights impinging on the openings of two metallic nanoslits and also shift their phases by pi difference. We elaborate the influence on the output effect from some geometrical parameters like the periodicity, the slit height, and so on. By controlling the light illuminated on metallic subwavelength apertures, it is practical to generate optical curtains of arbitrary forms, which may open new routes of plasmonic nanolithography.
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| 3. |
- Cui, Yanxia, et al.
(författare)
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Ultrabroadband Light Absorption by a Sawtooth Anisotropic Metamaterial Slab
- 2012
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 12:3, s. 1443-1447
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Tidskriftsartikel (refereegranskat)abstract
- We present an ultrabroadband thin-film infrared absorber made of sawtoothed anisotropic metamaterial. Absorptivity of higher than 95% at normal incidence is supported in a wide range of frequencies, where the full absorption width at half-maximum is about 86%. Such property is retained well at a very wide range of incident angles too. Light of shorter wavelengths are harvested at upper parts of the sawteeth of smaller widths, while light of longer wavelengths are trapped at lower parts of larger tooth widths. This phenomenon is explained by the slowlight modes in anisotropic metamaterial waveguide. Our study can be applied in the field of designing photovoltaic devices and thermal emitters.
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| 4. |
- Ding, Fei, et al.
(författare)
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Ultra-broadband microwave metamaterial absorber
- 2012
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 100:10, s. 103506-
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Tidskriftsartikel (refereegranskat)abstract
- A microwave ultra-broadband polarization-independent metamaterial absorber is demonstrated. It is composed of a periodic array of metal-dielectric multilayered quadrangular frustum pyramids. These pyramids possess resonant absorption modes at multi-frequencies, of which the overlapping leads to the total absorption of the incident wave over an ultra-wide spectral band. The experimental absorption at normal incidence is above 90% in the frequency range of 7.8-14.7 GHz, and the absorption is kept large when the incident angle is smaller than 60 degrees. The experimental results agree well with the numerical simulation.
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| 5. |
- He, Sailing, et al.
(författare)
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Optical nano-antennas and metamaterials
- 2009
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Ingår i: MATERIALS TODAY. - 1369-7021. ; 12:12, s. 16-24
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Tidskriftsartikel (refereegranskat)abstract
- We review some recent approaches to transmission enhancement and light harvesting based on optical nano-antennas and metamaterials. Nano-cavity antennas are used to enhance the extraordinary transmission of TM-polarized light through vertical nano-slits in a metal film. The enhanced transmission of TE-polarized waves through an array of subwavelength-slits in a thin metal film at low frequencies (including microwave) is also investigated. Light harvesting with a metamaterial cloaking shell is also demonstrated.
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| 6. |
- He, Sailing, et al.
(författare)
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Transmission enhancement, perfect absorption and field squeezing with nano-antennas and metamaterials
- 2009
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Ingår i: THEORETICAL AND COMPUTATIONAL NANOPHOTONICS. - : AIP. - 9780735407152 ; , s. 18-20
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Konferensbidrag (refereegranskat)abstract
- We report some of our recent progress in enhancing the extraordinary optical transmission (EOT), perfect absorption and field squeezing. Based on the excitation of surface plasmon waves in optical nano-antennas, the extraordinary transmission of light through a vertical nano-slit in a metal film is realized. Omni-directional, broadband and polarization-insensitive absorption of light is achieved in a thin metamaterial absorber which consists of cross-antennas and a metal ground. A dielectric split ring inside a permeability-near-zero metamaterial is used to squeeze electromagnetic energy and obtain strong magnetic field at the gap without using any resonance mechanism.
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| 7. |
- Li, Guohui, et al.
(författare)
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Efficient heat dissipation perovskite lasers using a high-thermal-conductivity diamond substrate
- 2023
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Ingår i: SCIENCE CHINA Materials. - : Springer Science and Business Media LLC. - 2095-8226 .- 2199-4501. ; 66:6, s. 2400-2407
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Tidskriftsartikel (refereegranskat)abstract
- Efficient heat dissipation that can minimize temperature increases in device is critical in realizing electrical injection lasers. High-thermal-conductivity diamonds are promising for overcoming heat dissipation limitations for perovskite lasers. In this study, we demonstrate a perovskite nanoplatelet laser on a diamond substrate that can efficiently dissipate heat generated during optical pumping. Tight optical confinement is also realized by introducing a thin SiO2 gap layer between nanoplatelets and the diamond substrate. The demonstrated laser features a Q factor of ∼1962, a lasing threshold of 52.19 µJ cm−2, and a low pump-density-dependent temperature sensitivity (∼0.56 ± 0.01 K cm2 µJ−1) through the incorporation of the diamond substrate. We believe our study could inspire the development of electrically driven perovskite lasers. [Figure not available: see fulltext.].
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| 8. |
- Li, Guohui, et al.
(författare)
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Localized Bound Multiexcitons in Engineered Quasi-2D Perovskites Grains at Room Temperature for Efficient Lasers
- 2023
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 35:20
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Tidskriftsartikel (refereegranskat)abstract
- Reducing the excitation threshold to minimize the Joule heating is critical for the realization of perovskite laser diodes. Although bound excitons are promising for low threshold laser, how to generate them at room temperature for laser applications is still unclear in quasi-2D perovskite-based devices. In this work, via engineering quasi-2D perovskite PEA2(CH3NH3)n-1PbnBr3n+1 microscopic grains by the anti-solvent method, room-temperature multiexciton radiative recombination is successfully demonstrated at a remarkably low pump density of 0.97 µJ cm−2, which is only one-fourth of that required in 2D CdSe nanosheets. In addition, the well-defined translational momentum in quasi-2D perovskite grains can restrict the Auger recombination which is detrimental to radiative emission. Furthermore, the quasi-2D perovskite grains are favorable for increasing binding energies of excitons and biexcitons and so as the related radiative recombination. Consequently, the prepared phase quasi-2D perovskite film renders a threshold of room-temperature stimulated emission as low as 13.7 µJ cm−2, reduced by 58.6% relative to the amorphous counterpart with larger grains. The findings in this work are expected to facilitate the development of solution-processable perovskite multiexcitonic laser diodes.
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| 9. |
- Li, Guohui, et al.
(författare)
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Room-Temperature Single-Mode Plasmonic Perovskite Nanolasers with Sub-Picosecond Pulses
- 2024
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Ingår i: Advanced Functional Materials. - 1616-301X.
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Tidskriftsartikel (refereegranskat)abstract
- With the explosive growth of communication traffic, increasing the modulation bandwidth of semiconductor lasers has attracted significant attention. However, after rapid progress is achieved, further increasing the modulation bandwidth of semiconductor lasers is hampered by the slow charge-carrier dynamics. Here, a room temperature, single-mode perovskite nanolaser with sub-picosecond pulses, enabled by high Purcell enhancement is reported. This enhancement is achieved via transferring an atomically smooth perovskite nanoplatelet onto the surface of an ultra-smooth SiO2/Ag film. This nanolaser features a low mode volume (V) as low as 0.137 µm3, a high-quality factor (Q) up to 2180, and a low lasing threshold of 36.65 µJ cm−2. The Q value of the laser is one order of magnitude higher than that of state-of-the-art nanolasers. The smoothness of both the nanoplatelet and the SiO2/Ag film in the laser is critical to achieving a high Purcell enhancement. Polarization analysis reveals that the laser emission consists of a transvere-magnetic (TM) polarized surface plasmon mode and a transverse-electric (TE) polarized photonic mode. Furthermore, ultrafast charge-carrier dynamics indicate the surface plasmon decay time can be as short as 0.6 ± 0.4 ps due to the high Purcell enhancement. This work opens up the possibility of developing nanolasers with high bandwidths and ultra-small sizes.
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| 10. |
- Liu, Qingkun, et al.
(författare)
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Self-Alignment of Plasmonic Gold Nanorods in Reconfigurable Anisotropic Fluids for Tunable Bulk Metamaterial Applications
- 2010
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 10:4, s. 1347-1353
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the bulk self-alignment of dispersed gold nanorods imposed by the intrinsic cylindrical micelle self-assembly in nematic and hexagonal liquid crystalline phases of anisotropic fluids. External magnetic field and shearing allow for alignment and realignment of the liquid crystal matrix with the ensuing long-range orientational order of well-dispersed plasmonic nanorods. This results in a switchable polarization-sensitive plasmon resonance exhibiting stark differences from that of the same nanorods in isotropic fluids. The device-scale bulk nanoparticle alignment may enable optical metamaterial mass production and control of properties arising from combining the switchable nanoscale structure of anisotropic fluids with the surface plasmon resonance properties of the plasmonic nanorods.
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