The main objective of this project is to exploit the exceptional spin properties of nitrogen vacancy (NV) centers in diamond to develop a quantum network based on cavity QED of NV centers. While spectacular advances have been made in using RF transitions of NV centers for coherent electron and nuclear spin control, there are considerable challenges for exploiting optical transitions in NV centers. Optical transitions of typical NV centers exhibit ...
The main objective of the program is to investigate various physical phenomena and device structures that can lead to potential applications to all optical storage and processing. The physical effects include electro-magnetic ally induced transparency (EIT), coherent population oscillation (CPO) in semiconductor quantum wells (QW) or dots. We carried out experimental implementation of EIT from electron spin coherence in a GaAs quantum well waveguide for the first time. We designed ...
We have demonstrated a mechanism of tunable optical delay that takes advantage of the strong Coulomb interactions between excitons and free carriers and uses optical injection of free carriers to broaden and bleach an exciton absorption resonance. Fractional delay exceeding 200% has been obtained for an 8 ps optical pulse propagating near the heavy-hole excitonic transition in a GaAs quantum well (QW). We have also developed a scheme of using ...
Research efforts have focused on the development and implementation of electromagnetically-induced transparency (EIT) from electron spin coherence in a semiconductor quantum well waveguide. Experimental studies have shown an induced transmission resonance arising from the electron spin coherence in the differential transmission spectrum. The induced resonance can be viewed as a signature of EIT from the electron spin coherence. Studies of the polarization and magnetic field dependence further confirm the physical ...
This final technical report summarizes research supported by ARO in two areas: electromagnetically induced transparency (EIT) from electron spin coherence and cavity QED with nitrogen vacancy (NV) centers in diamond nanocrystals. We have developed three different schemes to realize EIT using electron spin coherence in semiconductor quantum wells. The three schemes include the use of V-type three-level systems via heavy hole excitonic transitions in an external magnetic field in the ...
Optical resonant excitation of excitons with nearly monochromatic light of energy E leads to an optically induced polarization (coherence) and a population of excitons within Delta E of E where Delta E approx.-(H=bar) gamma h(Yh is the homogeneous linewidth of the exciton). The decay of this excitation must be characterized by the decay rate of the polarization (called the dephasing or transverse relaxation rate, gamma sub t=gamma h as well ...
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