Biomedical subjects

M G Payne

Publications and source records attributed to M G Payne.

13 recordsLinked to original sources

PubMed2006

Formation and propagation of coupled ultraslow optical soliton pairs in a cold three-state double- system.

We investigate the simultaneous formation and propagation of coupled ultraslow optical soliton pairs in a cold, lifetime-broadened three-state double-Lambda atomic system. Starting from the equations of motion of atomic response and two-mode probe-control electromagnetic fields, we derive coupled nonlinear Schrödinger equations that govern the nonlinear evolution of the envelopes of the probe fields in this four-wave mixing scheme by means of the standard method of multiple scales. We demonstrate that for weak probe fields and with suitable operation conditions, a pair of coupled optical solitons moving with remarkably slow propagating velocity can be established in such a highly resonant atomic medium. The key elements to such a shape preserving, well matched yet interacting soliton pair is the balance between dispersion effect and self- and cross-phase modulation effects of the system.

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PubMed2005

Formation and propagation of matched and coupled ultraslow optical soliton pairs in a four-level double- system.

We investigate the simultaneous formation and stable propagation of ultraslow optical soliton pairs in a lifetime broadened four-state atomic system under double-Lambda excitation with large one- and two-photon detunings. We show that detrimental probe field distortions due to strong dispersion effects under weak driving conditions can be well balanced by self- and cross-phase modulation effects, leading to a pair of temporal, group velocity, and amplitude matched ultraslow optical solitons of different frequencies.

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PubMed2005

Dynamics of ultraslow optical solitons in a cold three-state atomic system.

We present a systematic study on the dynamics of a ultraslow optical soliton in a cold, highly resonant three-state atomic system under Raman excitation. Using a method of multiple scales we derive a modified nonlinear Schrödinger equation with high-order corrections that describe effects of linear and differential absorption, nonlinear dispersion, delay response of nonlinear refractive index, diffraction, and third-order dispersion. Taking these effects as perturbations we investigate in detail the evolution of the ultraslow optical soliton using a standard soliton perturbation theory. We show that due to these high-order corrections the ultraslow optical soliton undergoes deformation, change of propagating velocity, and shift of oscillating frequency. In addition, a small radiation superposed by dispersive waves is also generated from the soliton. The results of the present work may provide a guidance that is useful for experimental demonstration of ultraslow optical soliton in cold atomic systems.

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PubMed2004

Efficient multiwave mixing in the ultraslow propagation regime and the role of multiphoton quantum destructive interference.

We analyze a lifetime-broadened four-state four-wave-mixing (FWM) scheme in the ultraslow propagation regime and show that the generated FWM field can acquire the same group velocity and pulse shape as those of an ultraslow pump field. We show that a new type of induced transparency resulted from multiphoton destructive interference that significantly reduced the pump field loss. Such induced transparency based on multphoton destructive interference may have important applications in other nonlinear optical processes.

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PubMed2003

Inhibiting the onset of the three-photon destructive interference in ultraslow propagation-enhanced four-wave mixing with dual induced transparency.

We propose a dual electromagnetically induced transparency (EIT) based multiwave mixing scheme that retains the significantly enhanced conversion efficiency enabled by ultraslow propagation of pump waves, yet is also capable of inhibiting and delaying the onset of the detrimental three-photon destructive interference that limits the further growth of the four-wave mixing (FWM) field. We show that the new scheme exhibits a wave-matching condition that is fundamentally different from the conventional FWM without EIT, and the efficient generation of the mixing wave is not critically dependent upon the FWM detuning to achieve constructive interference as required in the conventional FWM. These are significant steps forward in enabling applications of ultraslow wave nonlinear optics.

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PubMed2003

Quantum entanglement of Fock states with perfectly efficient ultraslow single-probe photon four-wave mixing.

We propose a method to achieve quantum entanglement of two Fock states with perfectly efficient, ultraslow propagation enhanced four-wave mixing. A cold atomic medium is illuminated with a two-mode cw control laser to produce coherent mixtures of excited states. An ultraslowly propagating, single-photon quantum probe field completes the four-wave mixing with 100% photon flux conversion efficiency, creating a depth dependent entanglement of two Fock states. We show that at a suitable propagation distance, a maximum entangled state is created with a single-photon wave-packet state that has 50% probability of being in each of two product-type Fock states.

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PubMed2002

Opening optical four-wave mixing channels with giant enhancement using ultraslow pump waves.

We show that by strongly modifying the dispersion properties of a four-level system, non-existing wave mixing channels can be opened and significantly enhanced. Specifically, we show that coherent optical four-wave mixing with a pump wave mediated by electromagnetically induced transparency (thereby propagating with an extremely slow group velocity) will lead to many orders of magnitude enhancement in the amplitude of the generated wave. Contrary to common belief, a large transparency window, which causes a large propagation velocity, actually diminishes efficient mixing wave production.

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PubMed1978