Chizari Ata, Abdollahramezani Sajjad, Jamali Mohammad Vahid, Salehi Jawad A
Opt Lett. 2016 Aug 1;41(15):3451-4. doi: 10.1364/OL.41.003451.
In this Letter, we realize the concept of analog computing using an engineered gradient dielectric meta-reflect-array. The proposed configuration consists of individual subwavelength silicon nanobricks, in combination with a fused silica spacer and silver ground plane, realizing a reflection beam with full phase coverage of 2π degrees, as well as an amplitude range of 0 to 1. Spectrally overlapping electric and magnetic dipole resonances, such high-index dielectric metasurfaces can locally and independently manipulate the amplitude and phase of the incident electromagnetic wave. This practically feasible structure overcomes substantial limitations imposed by plasmonic metasurfaces such as absorption losses and low polarization conversion efficiency in the visible range. Using such CMOS-compatible and easily integrable platforms promises highly efficient ultrathin planar wave-based computing systems that circumvent the drawbacks of conventional bulky lens-based signal processors. Based on these key properties and the general concept of spatial Fourier transformation, we design and realize broadband mathematical operators such as the differentiator and integrator in the telecommunication wavelengths.
在本信函中，我们利用一种工程化的梯度介电超表面反射阵列实现了模拟计算的概念。所提出的结构由单个亚波长硅纳米砖组成，与熔融石英间隔层和银接地平面相结合，实现了具有2π度全相位覆盖以及0到1幅度范围的反射光束。由于光谱重叠的电偶极和磁偶极共振，这种高折射率介电超表面可以局部且独立地操控入射电磁波的幅度和相位。这种切实可行的结构克服了等离子体超表面所带来的诸多限制，比如在可见光范围内的吸收损耗和低偏振转换效率。使用这种与CMOS兼容且易于集成的平台有望实现高效的基于超薄平面波的计算系统，从而规避传统基于笨重透镜的信号处理器的缺点。基于这些关键特性以及空间傅里叶变换的一般概念，我们在电信波长范围内设计并实现了诸如微分器和积分器等宽带数学运算器。
