Diebold Aaron V, Imani Mohammadreza F, Sleasman Timothy, Smith David R
Appl Opt. 2018 Mar 20;57(9):2142-2149. doi: 10.1364/AO.57.002142.
We demonstrate a dynamic metasurface aperture as a unique tool for computational ghost imaging at microwave frequencies. The aperture consists of a microstrip waveguide loaded with an array of metamaterial elements, each of which couples energy from the waveguide mode to the radiation field. With a tuning mechanism introduced into each independently addressable metamaterial element, the aperture can produce diverse radiation patterns that vary as a function of tuning state. Here, we show that fields from such an aperture approximately obey speckle statistics in the radiative near field. Inspired by the analogy with optical correlation imaging, we use the dynamic aperture as a means of illuminating a scene with structured microwave radiation, receiving the backscattered intensity with a simple waveguide probe. By correlating the magnitude of the received signal with the structured intensity patterns, we demonstrate high-fidelity, phaseless imaging of sparse targets. The dynamic metasurface aperture as a novel ghost imaging structure can find application in security screening, through-wall imaging, as well as biomedical diagnostics.
我们展示了一种动态超表面孔径，它是用于微波频率计算鬼成像的独特工具。该孔径由加载了超材料元件阵列的微带波导组成，每个超材料元件将能量从波导模式耦合到辐射场。通过在每个可独立寻址的超材料元件中引入调谐机制，该孔径可以产生随调谐状态而变化的各种辐射方向图。在这里，我们表明来自这种孔径的场在辐射近场中大致服从散斑统计。受与光学相关成像类比的启发，我们使用动态孔径作为用结构化微波辐射照亮场景的手段，并用简单的波导探头接收反向散射强度。通过将接收到的信号幅度与结构化强度模式相关联，我们展示了稀疏目标的高保真无相位成像。动态超表面孔径作为一种新型鬼成像结构，可应用于安全筛查、穿墙成像以及生物医学诊断。
