CAREER: Nonlinear Dynamics of Exciton-Polarons in Two-Dimensional Metal Halides Probed by Quantum-Optical Methods

职业：通过量子光学方法探测二维金属卤化物中激子极化子的非线性动力学

• 批准号: 2338663
• 负责人: Ajay Ram Srimath Kandada
• 金额: $ 66.95万
• 依托单位: Wake Forest University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-02-01 至 2029-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2338663&HistoricalAwards=false
• 关键词: CAREER; Nonlinear; Dynamics; Exciton; Polarons

With support from the Chemical Structure, Dynamics, and Mechanisms A (CSDM-A) program in the Division of Chemistry, Ajay Ram Srimath Kandada of Wake Forest University is incorporating quantum-optical principles into ultrafast nonlinear spectroscopy to investigate photo-excitation dynamics in materials close to the single-photon excitation limit. Nonlinear optical spectroscopy, which is widely used to explore light-matter interactions, requires high light intensities due to fundamental limitations in classical optical detection. Unfortunately, this often introduces significant ambiguity in the derived photophysical models. This research project seeks to overcome this limitation by harnessing the superior signal-to-noise ratio provided by quantum-optical methods. Dr. Srimath Kandada and his students will use this enhanced experimental capability to investigate the unique exciton physics of two-dimensional derivatives of metal halide perovskites. Improved comprehension of perovskite photophysics is expected to drive the optimization of their optoelectronic properties, with potential benefits for a variety of applications. The education and outreach program, centered on the optics and spectroscopy components of the research program, will build a synergistic partnership between the students and faculty at Wake Forest University and the local high schools to motivate greater participation of students from diverse backgrounds in STEM (science, technology, engineering and mathematics) education and research.This research project aims to measure the dynamics of exciton-lattice correlations and the fluctuations that drive them, to accurately estimate the intrinsic dephasing rate of excitons and inter-exciton interactions and to measure the dynamics of carrier thermalization and exciton formation without many-body contributions. The first part of the project will focus on the nature of polaronic coupling of photo-excitations in two-dimensional metal halides and the role of dynamic lattice fluctuations. The experiment involves the measurement of noise in the amplitude and phase of the transient optical response in the presence of an impulsively generated population of coherent phonons. This will enable the estimation of contributions from stochastic lattice fluctuations to the phonon anharmonicity and polaronic dressing of excitons. The second part of the project will employ quantum-entangled photons as a probe of many-body exciton dynamics. The energy correlations between a pair of spectrally entangled photons, transmitted through the resonant medium, is to be used to accurately estimate exciton dephasing rate and biexciton interactions, bereft of multi-order expansion issues. The photon entanglement is also to be exploited to measure the population dynamics of excitons at extremely low excitation densities in a (classical) pump - (quantum) probe experiment.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.

在化学结构，动力学和机制A（CSDM-A）程序中的支持下，Wake Forest University的Ajay Ram Srimath Kandada正在将量子 - 光学原理纳入超快非线性光谱中，以研究接近单光子激发极限的材料中的照片激发动力学。非线性光谱法被广泛用于探索光 - 物质相互作用，由于经典光学检测的基本限制，需要高光强度。不幸的是，这通常在派生的光物理模型中引入了明显的歧义。该研究项目旨在通过利用量子光学方法提供的出色信噪比来克服这一局限性。 Srimath Kandada博士和他的学生将使用这种增强的实验能力来研究金属卤化物钙钛矿的二维衍生物的独特激子物理学。预计对钙钛矿光物理学的理解有望提高其光电特性的优化，并具有各种应用的潜在好处。以研究计划的光学和光谱副本组成部分为中心的教育和宣传计划将在Wake Forest University和当地高中建立协同伙伴关系，以激发来自STEM的不同背景的学生更多地参与STEM（科学，技术，工程和数学研究）的教育和数学研究。估计激子和脱离相互作用的固有分类速率，并在没有多体贡献的情况下测量载体热化和激子形成的动力学。该项目的第一部分将重点介绍二维金属卤化物中光兴趣的二极化耦合的性质以及动态晶格波动的作用。该实验涉及在存在冲动产生的相干声子群体的情况下瞬时光学响应幅度和相位的噪声测量。这将使从随机晶格波动到语音非谐波和激子的二极化敷料的贡献估计。该项目的第二部分将采用量子键入的光子作为多体激子动力学的探针。通过谐振介质传输的一对频谱纠缠的光子之间的能量相关性用于准确估计激子的脱态率和比xciton的相互作用，多阶扩展问题的失败。还应利用光子的纠缠来衡量（经典）泵中极低激发密度的激励密度的人群动态 - （量子）探针实验。该奖项反映了NSF的法定任务，并被视为值得通过基金会的知识分子和更广泛的影响审查的审查标准来通过评估来通过评估来获得支持。