Cavity QED and Confined Phonons in Semiconductor Quantum Dots

本论文主要研究半导体量子点中受限声子的相干操控和腔QED。在胶体量子点中，如CdSe纳米晶，不仅电子能级，而且晶格振动都完全量子化。这些量子点中受限声子的性质将被研究和利用，以发展一个单个或一个量子点阵列强烈耦合到单一电磁场模式的介观系统。相干非线性光学技术将被发展并用于光学激发和探测这些量子点中的受限声子。在每个量子点单个声子的水平上进行光学操纵，以及了解量子化机械激发在纳米机械系统中的退相干是重要的目标。我们还将开发一种腔QED系统，在该系统中，受限声子通过驱动双光子拉曼跃迁耦合到熔融二氧化硅微球中的高Q耳语走廊模。所提出的腔QED系统为隔离和操纵简单量子系统中的基本动力学过程以及产生可控的量子点纠缠提供了一个独特的模型系统。除了在量子信息处理中的潜在应用外，光学操纵胶体量子点中的受限声子的能力也可以刺激这些量子点作为纳米机械系统在生物等领域的进一步应用。该研究项目为研究生和本科生提供在光学、半导体物理、纳米技术和量子信息等具有科学和技术重要性的领域的尖端研究技术方面的培训。这项培训将为他们在学术界、工业界和政府的一系列职业生涯做好准备。本研究项目主要研究半导体量子点中的电子激发和机械激发。在半导体量子点中，如尺寸为几纳米的CdSe纳米晶，电子和机械激发都是完全量子化的或完全离散的。我们将利用相干非线性光学技术研究电子和机械激发的性质，并将其用于发展单个或阵列量子点与单一电磁场强耦合的介观系统。这种复合量子点微腔系统可用于简单量子系统中动力学过程的相干操作和探索量子信息处理，这是一个具有相当重要技术意义的领域。半导体纳米晶体中机械激发的光学操纵能力也可以刺激这些量子点作为纳米机械系统在生物等领域的进一步应用。参与该项目的学生在光学、半导体物理、纳米技术和量子信息等领域接受严格的培训，这些领域既具有科学和技术重要性，又可以在学术界、工业界和政府追求职业生涯。

This research is focused on coherent manipulation and cavity QED of confined phonons in semiconductor quantum dots. In colloidal quantum dots such as CdSe nanocrystals, not only electronic energy levels but also lattice vibrations are completely quantized. Properties of confined phonons in these quantum dots will be investigated and exploited for the development of a mesoscopic system in which a single or an array of quantum dots couple strongly to a single mode of electromagnetic fields. Coherent nonlinear optical techniques will be developed and used for the optical excitation and detection of confined acoustic phonons in these quantum dots. Optical manipulation at the level of a single phonon per quantum dot, and understanding decoherence of quantized mechanical excitations in a nanomechanical system are important goals. A cavity QED system where confined acoustic phonons coupling to a high-Q whispering gallery mode in a fused silica microsphere through a driven two-photon Raman transition will also be developed. The proposed cavity QED system provides a unique model system for isolating and manipulating fundamental dynamical processes in simple quantum systems and for creating controlled entanglement of quantum dots. In addition to potential applications in quantum information processing, the ability of optical manipulation of confined phonons in colloidal quantum dots can also stimulate further applications of these quantum dots as nanomechanical systems in areas such as biology. The research program provides training for graduate and undergraduate students in cutting edge research techniques in areas including optics, semiconductor physics, nanotechnology, and quantum information that are of both scientific and technological importance. This training will prepare them for a range of careers in academe, industry, and government. This research program is focused on studies of electronic and mechanical excitations in semiconductor quantum dots. In semiconductor quantum dots such as CdSe nanocrystals with a dimension of a few nanometers, both electronic and mechanical excitations are completely quantized or completely discrete. Properties of electronic and mechanical excitations will be investigated by using coherent nonlinear optical techniques and will be exploited for the development of a mesoscopic system in which a single or an array of quantum dots couple strongly to a single mode of electromagnetic fields. This composite quantum dot microcavity system can be used for the coherent manipulation of dynamical processes in simple quantum systems and for the exploration of quantum information processing, an area of considerable technological importance. The ability of optical manipulation of mechanical excitations in semiconductor nanocrystals can also stimulate further applications of these quantum dots as nanomechanical systems in areas such as biology. Students involved in this program receive rigorous training in areas including optics, semiconductor physics, nanotechnology, and quantum information that are of both scientific and technological importance and can pursue careers in academe, industry, and government.