Strain engineering of exciton-polaritons in 2D Semiconductors

非技术描述原子薄的二维(2D)半导体由于其前所未有的与光的强相互作用，已经成为一种非常吸引人的应用于光子学的材料平台。从基本的观点来看，它们展示了一系列广泛的现象，包括强烈的光-物质相互作用制度，其中系统既表现出光的性质，也表现出物质的激发性质。这种混合系统在固态量子技术中具有潜在的应用，使它们能够呈现出物质和光的最佳性质。由于这些2D材料的原子厚度，应变为提高其光电性能提供了独特的途径。这项研究的重点是利用应变来控制这些混合体系的光电性质，并探索在晶格几何中引入应变时出现的性质。这种半光半物质系统的晶格可以实现对其他量子系统的模拟，这些系统很难在经典计算机上模拟。其他潜在的应用领域包括实现基于光的电路和开关，这些电路和开关可以在单个光粒子的水平上运行。该项目与美国国家科学基金会“量子飞跃”的宏伟构想相一致。它将培养研究生和本科生，并让当地中学的学生接触到光和纳米材料的奇迹。推广活动中的一个亮点是为城市学院的本科生举办的动手2D材料研讨会，以及为当地中学举办的一系列演示。技术说明激子-极化激子、电子材料激发和光子的混合态展示了一系列丰富的物理现象。它们是固态量子非线性光子学潜在的很好的平台。在这个项目中，研究小组将利用2D材料承受大应变的能力来操纵嵌入原子薄半导体的光学微腔中形成的激子和激子-极化子。通过衬底工程诱导极大的应变，控制应变模式，操纵激子和极化子的扩散，最终增强它们之间的非线性相互作用，实现极化子及其晶格的关联态。具体地说，研究中使用了嵌入应变工程微腔中的2D过渡金属二盐基化物。使用稳态、时间分辨和傅里叶空间光谱相结合的方法研究了它们的线性和非线性光学性质。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。

Nontechnical DescriptionAtomically thin two-dimensional (2D) semiconductors, owing to their unprecedented strong interaction with light have become a very attractive material platform for applications in photonics. From a fundamental standpoint, they demonstrate a wide array of phenomena including the regime of strong light-matter interaction where the system exhibits both the properties of light and material excitation. Such hybrid systems have potential applications in quantum technologies in the solid state that allow them to take on the best properties of matter and light. Due to the atomic thickness of these 2D materials, strain presents a unique approach to enhance the optoelectronic properties. This research is focusing on using strain to control the optoelectronic properties of these hybrid systems and to explore emergent properties that arise when strain is introduced in a lattice geometry. Such lattice of half-light half-matter systems can enable simulation of other quantum systems which are hard to simulate on a classical computer. Other potential application areas include realizing light-based circuits and switches which could conceivably operate at the level of a single particle of light. The project aligns with the NSF Big Idea of “Quantum Leap.” It will train graduate and undergraduate students and expose students from local area middle schools to the wonders of light and nanomaterials. A highlight among the outreach activities is a hands-on 2D materials workshop for undergraduate students at City College and a series of demonstrations for local area middle school.Technical DescriptionExciton-polaritons, hybrid states of electronic material excitations and photons demonstrate a wide array of rich physical phenomena. They are a potentially good platform for solid state quantum nonlinear photonics. In this project the research team will utilize the ability of 2D materials to withstand large strains to manipulate excitons and exciton-polaritons formed in optical microcavities embedded with atomically thin semiconductors. Extremely large strain via substrate engineering is induced to control strain patterns, manipulate exciton and polariton diffusion and finally enhance their nonlinear interactions for realizing correlated states of polaritons and their lattices. Specifically, 2D transition metal dichalcogenides embedded in strain engineered microcavities are used in the studies. Their linear and non-linear optical properties are investigated using combination of steady state, time resolved and Fourier space spectroscopy.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.