Controlled polarization in plasmons propagating from metal into semiconductors in multicomponent nanowires

摘要：目的：我们研究了光在由金属段和半导体段组成的纳米线中的传播，并观察到这两个部分之间可以实现有效的电和光耦合。我们假设，调整结的形状将控制从纳米线的远端半导体端发射的光相对于耦合到纳米线的金属端入射光的偏振旋转。我们的时域模拟再现了我们的许多初步观察结果。我们提出了优化非对称金属-半导体结的电和光传输，我们描述了一系列初步的化学传感实验。智力优势：等离子体激元在单组分金属纳米线中的传播已经被很好地理解，但在不同材料之间的传播仍在探索中。这种结构的偏振控制对于设计更大规模的器件是至关重要的，但这种结构的偏振操纵基本上是一个未被触及的研究领域。本项目将探索这些领域，并将研究这种极化旋转的潜在传感应用。更广泛的影响：对纳米级光子系统中极化的基本理解和控制将对国家安全和通信技术产生广泛的潜在影响。污染物和毒素的传感在社会和国家安全中具有明显的重要性，这些实验可能为纳米级传感器的新方法提供信息。此外，该项目将侧重于从代表性不足的群体（NSF-AGEP， SMART等）招募本科生和研究生。

ABSTRACT:Objective: We have studied the propagation of light in nanoscale wires comprising a metal segment and a semiconducting segment, and we have observed that efficient electrical and optical coupling can be achieved between these two segments. We posit that tailoring the shape of the junction will control the polarization rotation of the light emitted from the distal semiconducting end of the nanowire relative to incident light coupled into the metal end of the nanowire. Our time-domain simulations reproduce many of our preliminary observations. We propose to optimize the asymmetric metal-semiconductor junctions for electrical and optical transport, and we describe a series of preliminary chemical sensing experiments. Intellectual Merit: Propagation of plasmons in single-component metal nanowires is well understood, but propagation between different materials is still being explored. Control of polarization in such structures can be critical to the design of larger scale devices, but manipulation of the polarization in such structures is essentially untouched as a research field. This project will explore these areas, and will study potential sensing applications of this polarization rotation.Broader Impact: Fundamental understanding and control of polarization in nanoscale photonic systems will have broad potential impacts in the technology of national security and communications. Sensing of pollutants and toxins has obvious importance in society and national security and experiments here may inform new methods of nanoscale sensors. In addition this project will focus on the recruitment of both undergraduate and graduate students from under-represented groups (NSF-AGEP, SMART, eg).