在本文中,相同的V形金纳米结构和可变V形金纳米结构的周期性阵列被设计在具有薄的二氧化钒(VO2)间隔层的镀金二氧化硅(SiO2)衬底的顶部,以实现多波长和宽带等离子体开关,分别。具有小的粒子间分离的相同V形纳米结构(IVNS)的周期性阵列导致V形纳米结构(VNS)的基本等离子体激元的耦合相互作用,当入射光在x方向上偏振时,在所提出的开关的反射光谱中产生具有两个纵向等离子体激元模式的混合等离子体激元响应。X方向沿着连接周期性阵列的一个单位单元中的所有VNS的V结的轴取向。暴露在温度下,电场,或者光学刺激,VO2层从其单斜半导体状态转变为金红石金属状态,导致从所提出的纳米结构获得的反射光谱的整体变化,并导致有效的多波长切换作用。采用有限差分时域(FDTD)模型来证明,通过采用相同的V形纳米结构的周期性阵列,可以通过采用所提出的开关来实现在两个波长处的消光比>12dB。Further,基于可变V形纳米结构(VVNS)的等离子体开关-即,提出了在周期性阵列的一个单位单元中具有可变臂长度的多个VNS,用于宽带开关。在宽带操作模式下,我们报告了一个消光比>5分贝的工作波长范围>1400nm在近红外光谱范围跨越所有光通信频带,即,O,E,S,C,L和U波段。Further,还证明了这些开关的操作波长可以通过改变所提出的开关的几何参数来调节。这些交换机具有在通信网络中使用的潜力,其中不可避免地需要具有多波长操作或在宽操作带宽上切换的超小型和超快交换机。
In this paper, periodic arrays of identical V-shaped gold
nanostructures and variable V-shaped gold
nanostructures are designed on top of a gold-coated silicon dioxide (SiO2) substrate with a thin spacer layer of vanadium dioxide (VO2) to realize multi-wavelength and broadband plasmonic switches, respectively. The periodic array of identical V-shaped
nanostructures (IVNSs) with small inter-particle separation leads to coupled interactions of the elementary plasmons of a V-shaped nanostructure (VNS), resulting in a hybridized plasmon response with two longitudinal plasmonic modes in the reflectance spectra of the proposed switches when the incident light is polarized in the x-direction. The x-direction is oriented along the axis that joins the V-junctions of all VNSs in one unit cell of the periodic array. On exposure to temperature, electric field, or optical stimulus, the VO2 layer transforms from its monoclinic semiconducting state to its rutile metallic state, leading to an overall change in the reflectance spectra obtained from the proposed
nanostructures and resulting in an efficient multi-wavelength switching action. Finite difference time domain (FDTD) modelling is employed to demonstrate that an extinction ratio > 12 dB at two wavelengths can be achieved by employing the proposed switches by employing periodic arrays of identical V-shaped
nanostructures. Further, plasmonic switches based on variable V-shaped
nanostructures (VVNSs) - i.e., multiple VNSs with variable arm lengths in one unit cell of a periodic array - are proposed for broadband switching. In the broadband operation mode, we report an extinction ratio > 5 dB over an operational wavelength range > 1400 nm in the near-IR spectral range spanning over all optical communication bands, i.e., the O, E, S, C, L and U bands. Further, it is also demonstrated that the wavelength of operation for these switches can be tuned by varying the geometrical parameters of the proposed switches. These switches have the potential to be employed in communication networks where ultrasmall and ultrafast switches with multi-wavelength operation or switching over a wide operational bandwidth are inevitably required.