Optical Bound States and Non-linearity in Geometrically-Modulated Dielectric Nanowires

几何调制介电纳米线中的光学束缚态和非线性

• 批准号: 2121643
• 负责人: James Cahoon
• 金额: $ 54.56万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2121643&HistoricalAwards=false
• 关键词: Optical; Bound; States; Non; linearity

Nontechnical descriptionThe interaction of light with spherical or cylindrical particles of microscopic size has frequently been used to understand the general principles of how light interacts with matter of different sizes and shapes. For example, microscopic particles that are comparable to or smaller than the wavelength of light can give rise to surprisingly strong light scattering and absorption. Recently, it has become possible to make microscopic particles with shapes that go beyond simple cylinders to instead have periodic modulations in their size. Under the right conditions, these geometric modulations cause the particles to interact with light in a new way, giving rise to what is termed an “optical bound state in the continuum,” or BIC. This project uses a combination of theory, computation, synthesis, and measurement to understand how the geometry of microscopic particles can be used to control the properties of BICs. BICs are exciting because they dramatically increase the extent to which light interacts with particles. In some cases, the interaction is sufficiently strong to cause the particles to convert red or infrared light into blue or ultraviolet light, a “non-linear” effect. The results of this project provide the general principles for controlling BICs in geometrically-modulated particles, thus providing the fundamental principles for controlling light over a broad range of colors at a microscopic scale. The research effort involves undergraduate, graduate, and postdoctoral students in a project that bridges the interface between chemistry, physics, and engineering—providing breadth of experience in nanomaterial synthesis, microfabrication, spectroscopy, microscopy, and modeling.Technical DescriptionIn cylindrical dielectric particles, Mie resonances can cause surprisingly strong light scattering and light absorption, and the importance and interplay of Mie resonances, leaky-mode resonances, and guided modes in these structures has previously been studied. A relatively new class of resonance, the BIC, has been identified and can theoretically trap light for an infinite time in an ideal system. This project studies the fundamental light scattering, light absorption, and nonlinear properties of BICs in dielectric cylinders with nanoscale lateral size. The silicon structures are synthesized by a bottom-up vapor-liquid-solid process using in situ dopant modulation combined with wet-chemical etching to create precisely-defined morphology. Periodic modulation of the diameter of a dielectric cylinder is shown to introduce a range of BICs of different order, polarization, and symmetry type. Spectroscopic measurements on single NWs of controlled geometry are compared to theoretical models, providing validation of theoretical predictions. The capacity of BICs in silicon NWs to enable nonlinear effects by doubling or tripling the frequency of incoming light is also evaluated. Overall, the proposed study reveals the fundamental characteristics of BICs in dielectric cylinders and highlights important practical applications of these BIC modes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术描述光与微小尺寸的球形或圆柱形颗粒的相互作用经常被用来理解光如何与不同大小和形状的物质相互作用的一般原理。例如，与光波长相当或小于光波长的微小颗粒可以引起令人惊讶的强烈光散射和吸收。最近，已经有可能制造出形状超越简单圆柱体的微小粒子，取而代之的是它们的大小具有周期性的调制。在适当的条件下，这些几何调制使粒子与光以一种新的方式相互作用，产生所谓的“连续统中的光学束缚态”，或称BIC。这个项目结合了理论、计算、综合和测量，以了解微观粒子的几何形状如何可以用来控制BIC的性质。BIC是令人兴奋的，因为它们极大地增加了光与粒子相互作用的程度。在某些情况下，相互作用强到足以使粒子将红光或红外光转换成蓝光或紫外光，这是一种“非线性”效应。该项目的结果提供了控制几何调制粒子中BIC的一般原理，从而提供了在微观尺度上控制广泛颜色范围的光的基本原理。这项研究工作涉及本科生、研究生和博士后，该项目在化学、物理和工程之间架起了一座桥梁-提供了纳米材料合成、微制造、光谱、显微镜和建模方面的广泛经验。技术说明在柱状介质颗粒中，Mie共振可以引起令人惊讶的强烈光散射和光吸收，以前已经研究过这些结构中Mie共振、漏模共振和导模的重要性和相互作用。一种相对较新的共振，BIC，已经被识别出来，理论上可以在理想系统中捕获无限时间的光。本项目研究了横向尺寸为纳米级的介质柱中BIC的基本光散射、光吸收和非线性特性。硅结构是通过自下而上的气-液-固工艺合成的，采用原位掺杂调制和湿法化学腐蚀相结合的方法来产生精确定义的形貌。介质柱直径的周期性调制引入了一系列不同阶数、极化和对称类型的BIC。将控制几何形状的单个原子核的光谱测量结果与理论模型进行了比较，从而验证了理论预测。还评估了硅核中BIC通过将入射光的频率加倍或三倍来实现非线性效应的能力。总体而言，拟议的研究揭示了介质圆柱体中BIC的基本特征，并突出了这些BIC模式的重要实际应用。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Reconfigurable Complementary and Combinational Logic Based on Monolithic and Single‐Crystalline Al‐Si Heterostructures

• DOI: 10.1002/aelm.202200567
• 发表时间: 2022-08
• 期刊: Advanced Electronic Materials
• 影响因子: 6.2
• 作者: R. Böckle;M. Sistani;Martina Bažíková;L. Wind;Zahra Sadre‐Momtaz;M. D. den Hertog;Corban G. E. Murphey;J. Cahoon;W. Weber