This file includes:Section 1:Simulation methods Section 2:Field distribution of FW and SHW with homogeneous WS2 monolayer Section 3:Field distribution of FW and SHW with patterned WS2 monolayer Section 4:Asymmetric ou...This file includes:Section 1:Simulation methods Section 2:Field distribution of FW and SHW with homogeneous WS2 monolayer Section 3:Field distribution of FW and SHW with patterned WS2 monolayer Section 4:Asymmetric outcoupling rate of TE-type BIC Section 5:Quality factor of quasi-BIC for a finite size grating Section 6:A flow chart for designing the dual BICs scheme Section 7:TMDs monolayer orientation-dependent polarization-resolved SHG efficiency Section 8:SHG efficiency of homogeneous bulk GaP Section 9:Prospectives for experimental realizations Supplementary information for this paper is available at https://doi.org/10.29026/oea.2022.200097.展开更多
The emergence of two dimensional(2D)materials has opened new possibilities for exhibiting second harmonic genera-tion(SHG)at the nanoscale,due to their remarkable optical response related to stable excitons at room te...The emergence of two dimensional(2D)materials has opened new possibilities for exhibiting second harmonic genera-tion(SHG)at the nanoscale,due to their remarkable optical response related to stable excitons at room temperature.However,the ultimate atomic-scale interaction length with light makes the SHG of Transition Metal Dichalcogenides(TM-Ds)monolayers naturally weak.Here,we propose coupling a monolayer of TMDs with a photonic grating slab that works with doubly resonant bound states in the continuum(BIC).The BIC slabs are designed to exhibit a pair of BICs,reson-ant with both the fundamental wave(FW)and the second harmonic wave(SHW).Firstly,the spatial mode matching can be fulfilled by tilting FW's incident angle.We theoretically demonstrate that this strategy leads to more than four orders of magnitude enhancement of SHG efficiency than a sole monolayer of TMDs,under a pump light intensity of 0.1 GW/cm^(2).Moreover,we demonstrate that patterning the TMDs monolayer can further enhance the spatial overlap coefficient,which leads to an extra three orders of magnitude enhancement of SHG efficiency.These results demonstrate remarkable pos-sibilities for enhancing SHG with nonlinear 2D materials,opening many opportunities for chip-based light sources,nano-lasers,imaging,and biochemical sensing.展开更多
We demonstrate a high-Q perfect light absorber based on all-dielectric doubly-resonant metasurface.Leveraging bound states in the continuum(BICs)protected by different symmetries,we manage to independently manipulate ...We demonstrate a high-Q perfect light absorber based on all-dielectric doubly-resonant metasurface.Leveraging bound states in the continuum(BICs)protected by different symmetries,we manage to independently manipulate the Q factors of the two degenerate quasi-BICs through dual-symmetry perturbations,achieving precise matching of the radiative and nonradiative Q factors for degenerate critical coupling.We achieve a narrowband light absorption with a>600 Q factor and a>99%absorptance atλ_(0)=1550 nm on an asymmetric germanium metasurface with a 0.2λ_(0)thickness.Our work provides a new strategy for engineering multiresonant metasurfaces for narrowband light absorption and nonlinear applications.展开更多
文摘This file includes:Section 1:Simulation methods Section 2:Field distribution of FW and SHW with homogeneous WS2 monolayer Section 3:Field distribution of FW and SHW with patterned WS2 monolayer Section 4:Asymmetric outcoupling rate of TE-type BIC Section 5:Quality factor of quasi-BIC for a finite size grating Section 6:A flow chart for designing the dual BICs scheme Section 7:TMDs monolayer orientation-dependent polarization-resolved SHG efficiency Section 8:SHG efficiency of homogeneous bulk GaP Section 9:Prospectives for experimental realizations Supplementary information for this paper is available at https://doi.org/10.29026/oea.2022.200097.
基金financial supports from the National Natural Science Foundation of China(Grant No.11604150)Fundamental Research Funds for the Central Universities of China(Grant No.ZYGX2020J010)M.Rahmani.acknowledges support from the UK Research and Innovation Future Leaders Fellowship(MR/T040513/1)。
文摘The emergence of two dimensional(2D)materials has opened new possibilities for exhibiting second harmonic genera-tion(SHG)at the nanoscale,due to their remarkable optical response related to stable excitons at room temperature.However,the ultimate atomic-scale interaction length with light makes the SHG of Transition Metal Dichalcogenides(TM-Ds)monolayers naturally weak.Here,we propose coupling a monolayer of TMDs with a photonic grating slab that works with doubly resonant bound states in the continuum(BIC).The BIC slabs are designed to exhibit a pair of BICs,reson-ant with both the fundamental wave(FW)and the second harmonic wave(SHW).Firstly,the spatial mode matching can be fulfilled by tilting FW's incident angle.We theoretically demonstrate that this strategy leads to more than four orders of magnitude enhancement of SHG efficiency than a sole monolayer of TMDs,under a pump light intensity of 0.1 GW/cm^(2).Moreover,we demonstrate that patterning the TMDs monolayer can further enhance the spatial overlap coefficient,which leads to an extra three orders of magnitude enhancement of SHG efficiency.These results demonstrate remarkable pos-sibilities for enhancing SHG with nonlinear 2D materials,opening many opportunities for chip-based light sources,nano-lasers,imaging,and biochemical sensing.
基金supported by the National Natural Science Foundation of China(Nos.62105172 and 62005236)the Zhejiang Provincial Natural Science Foundation(No.LQ21F050004)+1 种基金the Ningbo Natural Science Foundation(No.202003N4102)the K.C.Wong Magna Fund in Ningbo University。
文摘We demonstrate a high-Q perfect light absorber based on all-dielectric doubly-resonant metasurface.Leveraging bound states in the continuum(BICs)protected by different symmetries,we manage to independently manipulate the Q factors of the two degenerate quasi-BICs through dual-symmetry perturbations,achieving precise matching of the radiative and nonradiative Q factors for degenerate critical coupling.We achieve a narrowband light absorption with a>600 Q factor and a>99%absorptance atλ_(0)=1550 nm on an asymmetric germanium metasurface with a 0.2λ_(0)thickness.Our work provides a new strategy for engineering multiresonant metasurfaces for narrowband light absorption and nonlinear applications.
