纳米标准与检测重点实验室第204期学术报告

报告题目：Quantum state control in single quantum dots and the coupling with photonic crystal cavities

报 告 人：许秀来 研究员，中国科学院物理研究所

时    间：2019年3月20日（周三）上午10: 00

地    点：南楼二层会议室

邀 请 人：刘新风 研究员

报告摘要：

We report on high-resolution photocurrent (PC) spectroscopies of a single self-assembled InAs/GaAs quantum dot (QD) embedded in an n-i-Schottky device with an applied magnetic field. When the magnetic field is applied in Voigt geometry, the mixture of bright and dark states results in an observation of dark exciton states. For a positive charged trions (X+) in a single quantum dot, giant enhancement of photocurrent has been achieved because of the Coulomb repulsion between the two holes.

In addition, photonic crystal cavities with high quality factors around 10000 are fabricated with single quantum dots located in antinode position of the cavity. Strong coupling for cavity QED between different excitonic states in a single quantum dot and the cavity will be presented, two-photon Rabi splitting in a strongly coupled cavity-dot system is demonstrated. Both exciton and biexciton transitions couple to a high quality factor photonic crystal cavity with large coupling strengths over 130 μeV. When the cavity to simultaneously couple with two exciton states, two-photon Rabi splitting between biexciton and cavity is achieved, which can be well reproduced by theoretical calculations with quantum master equations.

Finally, strong interactions between cavities and p-shell excitons with a great enhancement by the in situ wave-function control will be demonstrated because of the large wave-function extents and nonlocal interactions beyond the dipole approximation. A large coupling strength of 210 meV has been achieved, indicating the great potential of p-shell excitons for coherent information exchange.

报告人简介：

Dr. Xiulai Xu received BA degree in Electronic Engineering from the Jilin University in 1996, and Ph.D. degree from Cavendish Laboratory, University of Cambridge in 2005. He has been working as research scientist, senior research scientist in Hitachi Cambridge Laboratory from 2005-2011, and was also a research fellow in Clare Hall, University of Cambridge during 2009-2011. He is currently a professor with Institute of Physics, Chinese Academy of Sciences on quantum optoelectronics and nano-photonics.