The ability to control the spin of individual electrons in solids is a valuable tool for quantum information processing. But there are other degrees of freedom, such as an electron's energy level or the valence state of individual atoms, that would be useful to control as well. With the support from the Quantum Information Science (QIS) program in the Physics Division and the Chemical Measurements and Imaging (CMI) program in the Chemistry Division, Professor Meriles will explore how to use a combination of spin and valence state control to process information. Recent work on optical control of individual color centers in diamond, such as a nitrogen-vacancy defect, has led to stunning demonstrations of single electron spin control, millisecond-long spin lifetimes, entanglement, and quantum logic operations. Despite this progress, however, the understanding of the physics governing such defects is incomplete, due to the comparatively poor information on their charge dynamics. To address this lack of knowledge, this project will explore how to use both charge states and spin states - and their interplay - as a resource for quantum information science in the solid state. Coherent control of charge states in solids will also advance the understanding of fundamental chemical physics factors affecting charge dynamics.
The project tackles important questions concerning defect ionization and recombination with emphasis on exploring alternate charge inter-conversion mechanisms (such as, e.g., carrier trapping) as a means to generating desired charge states that are otherwise difficult to attain via direct optical excitation. The aim is to pioneer a path for photo-injecting spin-polarized electrons into the conduction band so as to experimentally determine for the first time the spin lifetime of free carriers in bulk diamond. Adding to these fundamental aspects, the project will lay the groundwork for a range of practical applications including, for example, the development of more efficient NV spin readout protocols and the first implementation of ponderomotive traps for carrier manipulation in the solid state. Beyond quantum information science, this work will positively impact the broad set of applications where point defects are used as local probes, for example, through more efficient spin readout schemes or through new forms of sensing based on the influence of the environment on the defect's charge dynamics. The knowledge to be gained may also help develop 3D high-density optical memories using the charge state as the basic bit of information; it may also pave the route to locally altering the crystal index of refraction so as to implement optically reconfigurable waveguides and other photonic structures. Besides the technological and scientific advantages, the proposed research is expected to have a broad educational outcome because it offers students a unique inter-disciplinary scientific education and the ability to interact with a wide network of collaborating labs. These partnerships not only provide a broad dissemination platform but also allow the PI to advance ongoing outreach programs designed to provide meaningful research experiences to underprivileged students through summer activities within CCNY and at host universities. These plans gain special meaning at City College, a minority serving institution with a uniquely diverse population of inner-city students.
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.
