Spatial and Temporal Control of Quantum Dots for On-Chip Integration.

Site-controlled Quantum Dots;Photonic Crystal Cavity;Quantum Information Processing;Physics;Science;Physics

Lee, JieunSteel, Duncan G. ;

University of Michigan

关键词: Site-controlled Quantum Dots;    Photonic Crystal Cavity;    Quantum Information Processing;    Physics;    Science;    Physics;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/108946/jieun_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Quantum dots are nanostructures that confine electrons in three spatial dimensions. Due to their discrete atom-like energy levels and localization from the environment, individual quantum dots have the potential to be used as solid-state qubits for quantum information processing. To enable such information processing in a scalable manner, it is necessary to integrate quantum dots on-chip to devices like photonic crystal cavities for building a hybrid interface of a light-matter coupled system. Motivated to develop an effective way to integrate quantum dots with photonic crystals, this thesis first investigates spatially controlled InAs quantum dots that are fabricated by focused-ion-beam milling and molecular-beam epitaxy. Here, multi-layers of InAs quantum dots on top of the site-controlled seed dots are fabricated and the linewidth of an individual dot as narrow as 160 ueV is measured, indicating an improved optical quality over single-layer quantum dot samples. In addition, a spatial map of the micro-photoluminescence of individual quantum dots is measured to verify the dot positions with diffraction-limited spatial resolution. Statistical analysis over 16 array sites shows that the seed dot positions have transferred to the upper layers with a finite spatial deviation due to the formation of mounds. In addition to an optical study of site-controlled quantum dots, the second part of this thesis investigates the temporal dynamics of self-assembled InAs quantum dots that are coupled to a photonic crystal cavity. By performing the luminescence intensity autocorrelation experiment, the Purcell enhanced emission from individual quantum dots resonant to a cavity mode is measured, demonstrating a temporal control of quantum dots through coupling to an optical nanocavity. The measurement of exciton and biexciton transitions reveals distinct autocorrelation signals which originate from their different nonlinearities. Finally, a quantum optical simulation incorporating the interaction between the laser pulses, cavity mode and atomic two-level system is used to support the experimental exciton autocorrelation data.