ERI: Development of light-emitting devices having intensive quantum-optical properties using a low-dimensional semiconducting material

在过去的几十年里，在制造纳米级结构和执行超快激光光谱方面取得了重大的技术进步。在极短的时间内（不到一纳秒）在极短的距离内（小于一微米）发生的物理或化学现象可以用这种先进的纳米制造工具和方法进行分析和理解。超荧光（SF）是一种在纳米尺度上由相互作用的发射体集合产生的集体光代，是一种迷人的量子现象。当光源在单模电磁场下产生强烈的短脉冲时，就会发生顺波。SF作为一种新型的明亮光源，在量子传感、超窄激光、基于光子的量子计算等方面有着丰富的应用前景。然而，SF的实现是具有挑战性的，因为它通常需要非常低的温度和严格的激励条件。该项目使用一种低维化合物半导体，称为准二维（2D）钙钛矿薄膜形式。事实上，在准二维钙钛矿薄膜中已经观察到室温SF，这表明室温SF是可行的，但是，这种SF的量子光学性质类似于传统的气相SF还有待探索。由于室温SF固有的势能，对固态准二维钙钛矿的SF进行细化并测量其精细的量子态具有迫切的重要性。所提出的工作将促进我们对强大的固态材料的集体光学效应的理解，并展示了设计和控制量子光输出特性的实用方法。该提案旨在通过将准二维钙钛矿结合到分布式反馈（DFB）谐振器中来开发控制sf激光相变的光学器件。具有准二维钙钛矿的工程单片谐振腔将为sf激光跃迁的相图提供光学可控性。除了重现现有结果外，该项目还将在飞秒时间尺度上进行时间分辨光致发光光谱，以研究准二维钙钛矿DFB谐振器的SF发射的动力学特性。本实验将测量相互作用发射体的相位同步所需的SF积累时间和光致发光衰减曲线的特征rabi型振荡，这意味着强光-物质耦合。此外，本项目将执行(2)波长相关的二阶相关函数的测量，这将揭示光子统计和聚束特性的sf。最后，利用同差探测层析成像，研究小组将(3)寻找它们的非经典光子态，如位移压缩态。SF在室温下的脉冲和量子特性可能为实现超快量子光源开辟了一条道路。光子器件制造和飞秒时间分辨光谱是该项目的主要实验任务，这也将允许开发钙钛矿以外的其他新兴光致发光材料。此外，该项目还涉及到密歇根理工大学量子光学实验室课程的开发。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智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

The last few decades have seen significant technological advances in fabricating nanometer-scale structures and performing ultrafast laser spectroscopies. Physical or chemical phenomena occurring in extremely small distances (less than one micrometer) for extremely short time durations (less than one nanosecond) can be analyzed and understood with such advanced nanofabrication tools and methodologies. Superfluorescence (SF), collective light generations from an ensemble of interacting emitters in a nanometer-sized dimension, is one of the fascinating quantum phenomena. SF occurs when the light emitters synchronously behave under a single-mode electromagnetic field as they generate intensive short pulses. As a new type of bright light source, SF may find rich applications in quantum sensing, ultranarrow laser, and photonic-based quantum computation. The realization of SF, however, is challenging because it usually requires very low temperatures and stringent excitation conditions. This project uses a low-dimensional compound semiconductor called quasi-two-dimensional (2D) perovskites in thin film form. Indeed, a room-temperature SF has been observed in quasi-2D perovskite thin films, demonstrating that a room-temperature SF is feasible, but still, the quantum-optical properties of this SF akin to traditional SFs of gaseous phases have yet to be explored. Because of the potential inherent in a room temperature SF, it is of pressing importance that SFs from solid-state quasi-2D perovskites are refined and their exquisite quantum states measured. The proposed work will advance our understanding of the collective optical effects from a robust solid-state material and show the practical way to engineer and control the output properties of the quantum lights. This proposal aims to develop optical devices that control SF-lasing phase transitions by incorporating quasi-2D perovskite onto distributed feedback (DFB) resonators. Engineering monolithic resonant cavities with quasi-2D perovskites will provide optical controllability over the phase diagrams of SF-lasing transitions. Besides reproducing the existing results, the proposed project will perform (1) time-resolved photoluminescence spectroscopy on a femtosecond time scale to examine the dynamical characteristics of the SF emission from quasi-2D perovskite DFB resonators. This experiment will measure the SF build-up time required for the phase-synchronization of interacting emitters and the characteristic Rabi-type oscillations of photoluminescence decay curves, implying a strong light-matter coupling. Moreover, this project will perform (2) measurements of wavelength-dependent second-order correlation functions that will reveal the photon statistics and bunching characteristics of SFs. Finally, using homodyne detection tomography, the research team will (3) search for their non-classical photon states, such as displaced squeezed states. The pulsed and quantum nature of SF at room temperature may open a route toward realizing an ultrafast quantum light source. Photonic device fabrication and femtosecond time-resolved spectroscopy are the major experimental tasks of the project, which will also allow the exploitation of other emerging photoluminescent materials beyond perovskites. In addition, this project involves the development of a quantum optics lab course at Michigan Tech.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.