Nonlinear Photonic Crystal Nanocavities and Waveguides

科学与工程目标：该研究将基于先前授予的突破，即单个量子点和光子晶体平板纳米腔之间的强耦合。强耦合纳米腔是缩小LED和VCSEL尺寸的自然纳米技术限制。通过增加Q（通过降低引入背景吸收的量子点密度）和降低偶极退相速率g（通过将量子点共振地泵入其基态或激发态）来寻求器件改进（更大的分裂与线宽比）。此外，量子点将在更短的波长（1000 nm）下生长，量子探测器和Ti：Sa激光器使量子研究更容易。为了让这些新的真正的量子纳米器件在量子信息处理中找到应用，它们需要更容易控制脉冲。纳米腔将耦合到光子晶体波导，因此光可以通过端射耦合或光栅耦合器有效地耦合进和耦合出。波导耦合将加速纳米腔非线性光开关和传输几何双稳态的研究，并最终将互连纳米腔形成基本的集成光路。与拥有光子晶体计算能力的谢勒教授（加州理工学院）和莫洛尼教授（亚利桑那州）的合作将有助于确定垂直接入和波导接入之间的权衡，并解释我们的实验测量结果。长期目标是利用强耦合的点-光子纠缠来构建量子相位门，并转移量子态，使空间距离远的量子点之间能够共享纠缠。两个研究生（一名非洲裔美国人）参加这一研究项目将获得经验，操纵和纳米定位半导体样品，分辨率有限的光学，连续和飞秒激光光谱，他们将在国际会议上分享他们的研究成果，并将其发表在权威和广泛的期刊上。纳米光子学行业受益于本科生和研究生在纳米器件的基本物理和实验技能的教育。该项目将进一步巩固与阿克塞尔谢勒在加州理工学院著名的光子晶体制造小组的富有成效的合作。这项研究将导致量子光学器件的基本理解的进步和半导体纳米器件的技术进步。对于量子点光子晶体激光器来说，使谐振腔越来越小、提高Q值和优化耦合对于围绕强耦合设计的器件同样重要。

Science and Engineering Goals: The research will be based on the previous-grant breakthrough of strong coupling between a single quantum dot and a photonic crystal slab nanocavity. Strong-coupling nanocavities are the natural nanotechnological limit for the shrinking size of LED's and VCSEL's. Device improvement (larger splitting-to-linewidth ratio) will be sought by increasing Q (by reducing the quantum dot density which introduces background absorption) and decreasing the dipole dephasing rate g (by pumping the dot resonantly into its ground or excited state). Also quantum dots will be grown at shorter wavelengths (1000nm) where quantum detectors and Ti:Sa lasers make quantum research easier. For these new truly quantum nanodevices to find applications in quantum information processing, they need to be more accessible to control pulses. The nanocavities will be coupled to photonic crystal waveguides so light can be coupled in and out efficiently via end-fire coupling or grating couplers. Waveguide coupling will accelerate the study of nanocavity nonlinear optical switching and bistability in transmission geometry and eventually will interconnect nanocavities to form rudimentary integrated optical circuits. Collaborations with Professors Scherer (Caltech) and Moloney (Arizona) who have photonic crystal computational capabilities will help to determine the tradeoff between vertical access and waveguide access and to interpret our experimental measurements. The long term goal is to utilize the strong coupling dot-photon entanglement to construct a quantum phase gate and to transfer a quantum state enabling the sharing of entanglement among spatially distant quantum dots.Broader Impact: The two graduate students (one African American) participating in this research project will gain experience with manipulating and nanopositioning semiconductor samples, resolution-limited optics, cw and fs laser spectroscopy, weak signal detection, quantum physics, etc. They will share their research results at international meetings and publish them in refereed and broad-audience journals. The nanophotonics industry benefits from the education of undergraduate and graduate students in the basic physics and experimental skills of nanodevices. This project will further solidify the productive collaboration with Axel Scherer's renowned photonic crystal fabrication group at Caltech. This research will lead to advances in the fundamental understanding of quantum optical devices and to technological progress in semiconductor nanodevices. Making the cavity smaller and smaller, increasing the Q, and optimizing the coupling are as important for quantum-dot photonic-crystal lasers as for devices designed around strong coupling.