Karim Md Ehsanul, Choudhury Sajid Muhaimin
Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology Dhaka 1205 Bangladesh
Department of Electrical and Electronic Engineering, BRAC University Dhaka 1212 Bangladesh.
RSC Adv. 2024 Sep 16;14(40):29215-29228. doi: 10.1039/d4ra03726j. eCollection 2024 Sep 12.
In this article, we report, to the best of our knowledge, for the first time, phase change material (PCM)-based reconfigurable metasurfaces for tailoring different degrees of freedom (DoF) of the quantum emitter (QE) emission, namely polarization and directionality, two key controlling factors in applications such as quantum computing, communication, and chiral optics. We have used a hybrid plasmon-QE coupled bullseye grating system utilizing the unexplored concept of composite nano-antennas in quantum photonics as the basic building block of the structures. Carefully engineered azimuthal width profile of the SbS/AlGaAs composite ridge and selectively controlled transition of PCM (SbS) states provide dynamic control over the amplitude and phase of the scattered radiation. Based on this methodology, we have designed five different metasurfaces for on-demand switching of target DoFs of QE emission, ensuring high collection efficiency due to the near-field coupling scheme. The first two metasurfaces switch the majority of the outgoing radiation from radially polarized to circularly polarized, whereas the next two switch the direction of circularly polarized outgoing radiation by a maximum of 9.23° while maintaining the spin state (or polarization chirality) in the simulation environment. The third metasurface category is capable of on-demand generation and separation of opposite spin states of outgoing radiation by 11.48° utilizing the selectively controlled phase transition of SbS. Such reconfigurable multi-dimensional manipulation of QE radiation has not been investigated previously. This work proves the vast potential of active metasurfaces to modify the DoFs of QE emission, paving the way for high-dimensional quantum sources for high-speed quantum communication, higher dimensional quantum processing, and switchable chiral optics.
在本文中，据我们所知，我们首次报道了基于相变材料（PCM）的可重构超表面，用于调控量子发射器（QE）发射的不同自由度（DoF），即偏振和方向性，这是量子计算、通信和手性光学等应用中的两个关键控制因素。我们使用了一种混合等离子体 - QE耦合的靶心光栅系统，该系统利用了量子光子学中尚未探索的复合纳米天线概念作为结构的基本构建单元。精心设计的SbS/AlGaAs复合脊的方位角宽度分布以及对PCM（SbS）状态的选择性控制转变，可对散射辐射的幅度和相位进行动态控制。基于此方法，我们设计了五种不同的超表面，用于按需切换QE发射的目标DoF，由于近场耦合方案，确保了高收集效率。前两种超表面将大部分出射辐射从径向偏振切换为圆偏振，而后两种在模拟环境中切换圆偏振出射辐射的方向，最大可达9.23°，同时保持自旋状态（或偏振手性）。第三类超表面能够利用SbS的选择性控制相变，按需生成并分离出射辐射的相反自旋状态，角度为11.48°。此前尚未研究过这种对QE辐射的可重构多维操纵。这项工作证明了有源超表面在修改QE发射的DoF方面具有巨大潜力，为高速量子通信、高维量子处理和可切换手性光学的高维量子源铺平了道路。
