It has been found that the dielectric constants of transparent conductive oxides(TCOs)can be adjusted in an extremely large range by tuning the carrier density.Due to the remarkable light confinement property of the e...It has been found that the dielectric constants of transparent conductive oxides(TCOs)can be adjusted in an extremely large range by tuning the carrier density.Due to the remarkable light confinement property of the epsilon-near-zero(ENZ)effect of TCOs,it has attracted extensive interests of light modulation.However,the operation wavelength bandwidth is usually limited by optical resonance that is applied to enhance the light-TCOs interaction.In this work,a dual-resonance light coupling scheme is proposed to expand the modulation depth-bandwidth product with almost one order-of-magnitude improvement.In a metallic subwavelength grating structure with deep trenches backed by a ground plane,the ENZ mode can be coupled to both magnetic resonance and Fabry-Perot resonance respectively by tuning the bias.Decent light modulation can be obtained in a large operation wavelength band covering two resonances by optimizing the dual-resonance configuration.Such a reconfigurable efficient broadband modulation is important for robust communication link and possesses remarkable capacity for wavelength division multiplexing.展开更多
Titanium nitride(TiN) as a refractory plasmonic material is proposed to be used as an angle-insensitive integrated broadband solar absorber and narrowband near-infrared(NIR) emitter for solar thermo-photovoltaic(STPV)...Titanium nitride(TiN) as a refractory plasmonic material is proposed to be used as an angle-insensitive integrated broadband solar absorber and narrowband near-infrared(NIR) emitter for solar thermo-photovoltaic(STPV) application. By constructing TiN-nanopatterns/dielectric/TiN stack metamaterial, approximately 93% light absorption in a wavelength range of 0.3–0.9 μm and near unit narrowband(Δλ∕λ~0.3) emission in NIR(~2 μm) were demonstrated by numerical simulation. Keeping the excellent light absorption in the visible band, the emission wavelength can be easily tuned by patterning the top TiN layer into various subwavelength structures. This dual function attributes to the intrinsic absorption and plasmonic property of TiN. In such an integrated structure,broadband absorption and narrowband emission need to be balanced for an optimized power efficiency conversion. Detailed analysis has demonstrated that the STPV system based on this integrated absorber/emitter canexceed the Shockley–Queisser limit at 1000 K.展开更多
基金financial supports from the National Key Research and Development Program of China(No.2019YFB2203402)the National Natural Science Foundation of China(Nos.92050108,11774383,11774099 and 11874029)+2 种基金Guangdong Science and Technology Program International Cooperation Program(No.2018A050506039)Guangdong Basic and Applied Basic Research Foundation(No.2020B1515020037)Pearl River Talent Plan Program of Guangdong(No.2019QN01X120).
文摘It has been found that the dielectric constants of transparent conductive oxides(TCOs)can be adjusted in an extremely large range by tuning the carrier density.Due to the remarkable light confinement property of the epsilon-near-zero(ENZ)effect of TCOs,it has attracted extensive interests of light modulation.However,the operation wavelength bandwidth is usually limited by optical resonance that is applied to enhance the light-TCOs interaction.In this work,a dual-resonance light coupling scheme is proposed to expand the modulation depth-bandwidth product with almost one order-of-magnitude improvement.In a metallic subwavelength grating structure with deep trenches backed by a ground plane,the ENZ mode can be coupled to both magnetic resonance and Fabry-Perot resonance respectively by tuning the bias.Decent light modulation can be obtained in a large operation wavelength band covering two resonances by optimizing the dual-resonance configuration.Such a reconfigurable efficient broadband modulation is important for robust communication link and possesses remarkable capacity for wavelength division multiplexing.
基金supported by grants from the National Natural Science Foundation of China (Nos. 11274344 and 61574158)the Suzhou Science and Technology Development Program Foundation (No. ZXG201425)the general financial grant from the China Postdoctoral Science Foundation (No. 2014M560457)
文摘Titanium nitride(TiN) as a refractory plasmonic material is proposed to be used as an angle-insensitive integrated broadband solar absorber and narrowband near-infrared(NIR) emitter for solar thermo-photovoltaic(STPV) application. By constructing TiN-nanopatterns/dielectric/TiN stack metamaterial, approximately 93% light absorption in a wavelength range of 0.3–0.9 μm and near unit narrowband(Δλ∕λ~0.3) emission in NIR(~2 μm) were demonstrated by numerical simulation. Keeping the excellent light absorption in the visible band, the emission wavelength can be easily tuned by patterning the top TiN layer into various subwavelength structures. This dual function attributes to the intrinsic absorption and plasmonic property of TiN. In such an integrated structure,broadband absorption and narrowband emission need to be balanced for an optimized power efficiency conversion. Detailed analysis has demonstrated that the STPV system based on this integrated absorber/emitter canexceed the Shockley–Queisser limit at 1000 K.