Low-distortion slow light using two absorption resonances

We consider group delay and broadening using two strongly absorbing and widely spaced resonances. We derive relations which show that very large pulse bandwidths coupled with large group delays and small broadening can be achieved. Unlike single resonance systems, the dispersive broadening dominates the absorptive broadening which leads to a dramatic increase in the possible group delay. We show that the double resonance systems are excellent candidates for realizing all-optical delay lines. We report on an experiment which achieved up to 50 pulse delays with 40% broadening.Comment: 4 pages 4 figure

Transients of the Electromagnetically-Induced-Transparency-Enhanced Refractive Kerr Nonlinearity

We report observations of the dynamics of electromagnetically induced transparency (EIT) in a Λ system when the ground states are Stark shifted. Interactions of this type exhibit large optical nonlinearities called Kerr nonlinearities, and have numerous applications. The EIT Kerr nonlinearity is relatively slow, which is a limiting factor that may make many potential applications impossible. Using rubidium atoms, we observe the dynamics of the EIT Kerr nonlinearity using a Mach-Zehnder interferometer to measure phase modulation of the EIT fields resulting from a pulsed signal beam Stark shifting the ground state energy levels. The rise times and transients agree well with theory

Electromagnetically Induced Transparency Line Shapes for Large Probe Fields and Optically Thick Media

We calculate the line shape and linewidths for electromagnetically induced transparency (EIT) in optically thick, Doppler broadened media (buffer gasses are also considered). In generalizing the definition of the EIT linewidth to optically thick media, we find two different linewidth definitions apply depending on whether the experiment is pulsed or continuous wave (cw). Using the cw definition for the EIT line shape we derive analytic expressions describing the linewidth as a function of optical depth. We also review the EIT line shapes in optically thin media and provide physical arguments for how the line shapes change as a function of various parameters

Transients of the Electromagnetically-Induced-Transparency-Enhanced Refractive Kerr Nonlinearity: Theory

We present a theory describing the transients and rise times of the refractive Kerr nonlinearity which is enhanced using electromagnetically induced transparency (EIT). We restrict our analysis to the case of a pulsed signal field with continuous-wave EIT fields, and all fields are well below saturation. These restrictions enable the reduction of an EIT Kerr, four-level, density-matrix equation to a two-level Bloch-vector equation which has a simple and physically intuitive algebraic solution. The physically intuitive picture of a two-level Bloch vector provides insights that are easily generalized to more complex and experimentally realistic models. We consider generalization to the cases of Doppler broadening, many-level EIT systems (we consider the D1 line of 87Rb), and optically thick media. For the case of optically thick media we find that the rise time of the refractive EIT Kerr effect is proportional to the optical thickness. The rise time of the refractive EIT Kerr effect sets important limitations for potential few-photon applications

Slow Light with Large Fractional Delays By Spectral Hole-Burning in Rubidium Vapor

We report on the experimental realization of large fractional pulse delays in a hot, Doppler-broadened rubidium vapor. A pump laser burns a deep spectral hole in the inhomogeneously broadened vapor. The delay is shown to be widely tunable by both power broadening the resonance and frequency modulating the pump laser. The simplicity of the scheme opens up the possibility for practical optical delays and buffers

Low-Distortion Slow Light Using Two Absorption Resonances

We consider group delay and broadening using two strongly absorbing and widely spaced resonances. We derive relations which show that very large pulse bandwidths coupled with large group delays and small broadening can be achieved. Unlike single resonance systems, the dispersive broadening dominates the absorptive broadening which leads to a dramatic increase in the possible group delay. We show that the double resonance systems are excellent candidates for realizing all-optical delay lines. We report on an experiment which achieved up to 50 pulse delays with 40% broadening

Wide-bandwidth, tunable, multiple-pulse-width optical delays using slow light in cesium vapor

We demonstrate an all-optical delay line in hot cesium vapor that tunably delays 275 ps input pulses up to 6.8 ns and 740 input ps pulses up to 59 ns (group index of approximately 200) with little pulse distortion. The delay is made tunable with a fast reconfiguration time (hundreds of ns) by optically pumping out of the atomic ground states.Comment: 4 pages, 6 figure

Wide-Bandwidth, Tunable, Multiple-Pulse-Width Optical Delays Using Slow Light in Cesium Vapor

We demonstrate an all-optical delay line in hot cesium vapor that tunably delays 275 ps input pulses up to 6.8 ns and 740 input ps pulses up to 59 ns (group index of approximately 200) with little pulse distortion. The delay is made tunable with a fast reconfiguration time (hundreds of ns) by optically pumping out of the atomic ground states

Boundary Conditions on Internal Three-Body Wave Functions

For a three-body system, a quantum wave function $\Psi^\ell_m$ with definite $\ell$ and $m$ quantum numbers may be expressed in terms of an internal wave function $\chi^\ell_k$ which is a function of three internal coordinates. This article provides necessary and sufficient constraints on $\chi^\ell_k$ to ensure that the external wave function $\Psi^\ell_m$ is analytic. These constraints effectively amount to boundary conditions on $\chi^\ell_k$ and its derivatives at the boundary of the internal space. Such conditions find similarities in the (planar) two-body problem where the wave function (to lowest order) has the form $r^{|m|}$ at the origin. We expect the boundary conditions to prove useful for constructing singularity free three-body basis sets for the case of nonvanishing angular momentum.Comment: 41 pages, submitted to Phys. Rev.