Biomedical subjects

Ite A Yu

Publications and source records attributed to Ite A Yu.

5 recordsLinked to original sources

PubMed2006

Manipulating the retrieved frequency and polarization of stored light pulses.

We have experimentally demonstrated that stored and retrieved light pulses have different frequencies but maintain phase coherence; a stored light pulse is released with a different polarization. However, the manipulation process causes an energy loss of the retrieved pulse. We have discovered that Clebsch-Gordan coefficients among the Zeeman sublevels play an important role in the energy loss and have demonstrated a solution for avoiding the energy loss.

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PubMed2006

Low-light-level all-optical switching.

We propose an all-optical switch that utilizes the technique of storage and retrieval of light pulses. A single photon (probe pulse) switched by another (switching pulse) is feasible, and the on-off ratio can be as large as 10 dB. We have experimentally demonstrated that the energy of the retrieved probe pulse is reduced to about 10% because of the presence of a switching pulse with an energy per unit area of one photon per lambda(2)/(2pi). The achieved result does not depend on the coupling intensity, the atomic optical density, or the width and shape of the switching pulse.

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PubMed2006

Low-light-level cross-phase-modulation based on stored light pulses.

We experimentally demonstrate a low-light-level cross-phase-modulation (XPM) scheme based on the light-storage technique in laser-cooled 87Rb atoms. The proposed scheme can achieve a similar phase shift and has the same figure of merit as one using static electromagnetically induced transparency under the constant coupling field. Nevertheless, the phase shift and the energy loss of a probe pulse induced by a signal pulse are neither influenced by the coupling intensity nor by the atomic optical density in the light-storage XPM scheme. This scheme enhances the flexibility of the experiment and makes possible conditional phase shifts on the order of pi with single photons.

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PubMed2005

Adomian's decomposition method for electromagnetically induced transparency.

We developed the Adomian's decomposition method to work for the electromagnetically induced transparency (EIT) problem. The method is general and capable to solve the coupled nonlinear partial differential equations for a light pulse passing through a three-level -type coherent medium. This EIT system is described by the coupled Maxwell-Schrödinger equations and optical Bloch equations. In the weak probe field case, the results agree with perturbation solutions and experimental data. In the stronger probe field case while perturbation may fail, our results reproduce experimental data well. With the techniques of spatial and time partitions, we extend the decomposition method that will be versatile for the investigation of the light pulse propagating through a coherent atomic medium.

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PubMed2005

Low-light-level photon switching by quantum interference.

We report an experimental demonstration of low-light-level photon switching by quantum interference in laser-cooled 87Rb atoms. A resonant probe pulse with an energy per unit area of one photon per lambda2/2pi propagates through the optically thick atoms. Its energy transmittance is greater than 63%, or a loss of less than e(-1), because of the effect of electromagnetically induced transparency. In the presence of a switching pulse with an energy per unit area of 1.4 photons per lambda2/2pi, the energy transmittance of the same probe pulse becomes less than 37%, or e(-1). This substantial reduction of probe transmittance caused by switching photons may lead to potential applications in single-photon-level nonlinear optics and manipulation of quantum information.

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