9,118 research outputs found
All-optical control of molecular fluorescence
We present a quantum electrodynamical procedure to demonstrate the all-optical control of molecular fluorescence. The effect is achieved on passage of an off-resonant laser beam through an optically activated system; the presence of a surface is not required. Following the derivation and analysis of the all-optical control mechanism, calculations are given to quantify the significant modification of spontaneous fluorescent emission with input laser irradiance. Specific results are given for molecules whose electronic spectra are dominated by transitions between three electronic levels, and suitable laser experimental methods are proposed. It is also shown that the phenomenon is sensitive to the handedness of circularly polarized throughput, producing a conferred form of optical activity
Optical control of excited-state lifetimes
Electronic excitation of particles in fluorescent materials can now be controlled using laser-assisted energy-transfer techniques
Coherent Quantum Optical Control with Subwavelength Resolution
We suggest a new method for quantum optical control with nanoscale
resolution. Our method allows for coherent far-field manipulation of individual
quantum systems with spatial selectivity that is not limited by the wavelength
of radiation and can, in principle, approach a few nanometers. The selectivity
is enabled by the nonlinear atomic response, under the conditions of
Electromagnetically Induced Transparency, to a control beam with intensity
vanishing at a certain location. Practical performance of this technique and
its potential applications to quantum information science with cold atoms,
ions, and solid-state qubits are discussed.Comment: 4 pages, 2 figures. V2: changes in presentation (text, figures,
tables) and new references - final version as published in Phys. Rev. Lett
Fast optical preparation, control, and readout of a single quantum dot spin
We propose and demonstrate the sequential initialization, optical control, and readout of a single spin trapped in a semiconductor quantum dot. Hole spin preparation is achieved through ionization of a resonantly excited electron-hole pair. Optical control is observed as a coherent Rabi rotation between the hole and charged-exciton states, which is conditional on the initial hole spin state. The spin-selective creation of the charged exciton provides a photocurrent readout of the hole spin state. © 2008 The American Physical Society
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