Topological Photodetectors

拓扑光电探测器

• 批准号: 2230240
• 负责人: Ritesh Agarwal
• 金额: $ 38万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2230240&HistoricalAwards=false
• 关键词: Topological; Photodetectors

Photodetectors are devices which detect the presence of light and are very important components for applications in spectroscopy, imaging, diagnostics and for driving our information technology infrastructure. Conventional photodetectors detect optical power, i.e., convert the total number of photons impinging on the active area into a corresponding current. Therefore, most applications involving light utilize intensity to encrypt or decrypt information, i.e., by modulating the intensity of light at different wavelengths to encode information and counting the total number of photons at the detector end. However, light can also be engineered to carry much more information encoded in its phase and the direction of the oscillation of electric field. Vortex light is an example of a complex type of light which can be used to carry much more information that conventional light beams. However, it is not easy to detect and distinguish different types of vortex beams for on-chip applications. In this project, new types of quantum materials will be explored along with specially designed devices to assemble on-chip photodetectors that will produce different currents depending on the nature and type of light vortices. These new types of photodetectors can increase the information carrying capacity of our optical systems by utilizing more degrees of freedom of light than conventional systems that can enable us to continue to meet the ever-increasing demands on our devices to process more information. Research and educational activities will be integrated by the involvement of undergraduates in the research program, incorporating latest research results in the teaching modules, and training high school and college teachers from the Philadelphia district with student population from minority and underrepresented sections.On-chip topological photodetectors working at room temperature that are sensitive to different spin (SAM) and orbital angular momentum (OAM) states of topological (vortex) light will be developed. These topological photodetectors can enable a nonlinear scaling of information carrying capacity of optical systems that still mostly rely on optical power. At a fundamental level, the proposed studies will pave the way to understanding and engineering novel optoelectronic response in quantum topological materials via symmetry and geometry concepts. The project will extend these ideas to design the next generation of photodetectors with enhanced functionalities to replace bulky table-top optics currently used for sensing OAM modes of light. To develop on-chip topological photodetectors, materials that have a photoresponse sensitive to complex phase and intensity distribution of the OAM modes along with sensitivity to photon spin (polarization) will be explored. Most materials are neither sensitive to optical polarization nor the spatial or phase gradients of the optical beam, which makes this task challenging. For this purpose, topological Weyl semimetals will be studied due to their unique symmetry that can support OAM-SAM sensitive and strong nonlocal photoresponse at room temperature. By utilizing artificial neural network algorithms, these devices will then be trained to read out the OAM-SAM modes with high fidelity for applications in imaging, spectroscopy, and integrated systems for processing much larger bandwidth information.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.

光电探测器是一种检测光存在的设备，是光谱学、成像、诊断和驱动信息技术基础设施应用的重要组成部分。传统的光电探测器检测光功率，即将撞击有源区域的光子总数转换为相应的电流。因此，大多数涉及光的应用都是利用强度来加密或解密信息，即通过调制不同波长的光的强度来编码信息，并计算探测器端的光子总数。然而，光也可以被设计成携带更多的信息编码在它的相位和电场振荡的方向。涡旋光是一种复杂类型的光的一个例子，它可以用来携带比传统光束更多的信息。然而，对于片上应用来说，检测和区分不同类型的涡旋光束并不容易。在这个项目中，新型量子材料将与专门设计的设备一起探索，以组装芯片上的光电探测器，这些探测器将根据光漩涡的性质和类型产生不同的电流。这些新型的光电探测器可以通过利用比传统系统更多的光自由度来增加我们光学系统的信息承载能力，从而使我们能够继续满足对我们的设备处理更多信息的不断增长的需求。研究和教育活动将通过本科生参与研究项目，将最新的研究成果纳入教学模块，并培训来自费城地区的高中和大学教师，学生来自少数民族和代表性不足的地区。在室温下工作的片上拓扑光电探测器对拓扑（涡旋）光的不同自旋（SAM）和轨道角动量（OAM）状态敏感。这些拓扑光电探测器可以实现主要依赖于光功率的光学系统的信息承载能力的非线性缩放。在基础层面上，提出的研究将通过对称和几何概念为理解和设计量子拓扑材料中的新型光电响应铺平道路。该项目将扩展这些想法，设计具有增强功能的下一代光电探测器，以取代目前用于感应OAM光模式的笨重的桌面光学器件。为了开发片上拓扑光电探测器，将探索对OAM模式的复杂相位和强度分布具有光响应敏感性以及对光子自旋（偏振）敏感的材料。大多数材料对光偏振和光束的空间或相位梯度都不敏感，这使得这项任务具有挑战性。为此，拓扑Weyl半金属由于其独特的对称性，可以在室温下支持OAM-SAM敏感和强的非局部光响应，因此将进行研究。通过利用人工神经网络算法，这些设备将被训练以高保真度读出OAM-SAM模式，用于成像、光谱和处理更大带宽信息的集成系统。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。