dhbradshaw's slow-light [13 articles]

Abstract

The propagation of light in dispersive media is a subject of fundamental as well as practical importance. In recent years attention has focused in particular on how refractive index can vary with frequency in such a way that the group velocities of optical pulses can be much greater or much smaller than the speed of light in vacuum, or in which the refractive index can be negative. Treating these topics at an introductory to intermediate level, Fast Light, Slow Light and Left-Handed Light focuses on the basic ...

Abstract

Stationary light pulses (SLPs), i.e., light pulses without motion, are formed via the retrieval of stored probe pulses with two counter-propagating coupling fields. We show that there exist non-negligible hybrid Raman excitations in media of cold atoms that prohibit the SLP formation. We experimentally demonstrate a method to suppress these Raman excitations and realize SLPs in laser-cooled atoms. Our work opens the way to SLP studies in cold as well as in stationary atoms and provides a new avenue to low-light-level nonlinear optics. ...

Note (first note only)

Slow light, but not through an adiabatic decrease in pump strength. Slow light, but with the energy maintained in field form so that it can interact with an atom over a longer period of time.

Abstract

We present an analysis of the propagation of light pulses through materials possessing extreme values of the group velocity. We begin with an analysis of the behaviour that occurs upon propagation through materials possessing simple Lorentzian gain or absorption lines or materials possessing sharp dips in gain or absorption features. We also describe how more complicated lineshapes can be used to tailor the dispersion of a slow-light system. We furthermore present an analysis of fundamental limitations to how many pulse widths ...

Abstract

By embedding an atom capable of electromagnetically induced transparency inside an appropriate photonic-crystal microcavity it may become possible to realize an optical nonlinearity that can impart a π -rad-peak phase shift in response to a single-photon excitation. Such a device, if it operated at high fidelity, would then complete a universal gate set for all-optical quantum computation. It is shown here that the causal, noninstantaneous behavior of any χ (3) nonlinearity is enough to preclude such a high-fidelity ...

Abstract

Techniques to facilitate controlled interactions between single photons and atoms are now being actively explored1, 2, 3, 4, 5, 6, 7. These techniques are important for the practical realization of quantum networks, in which multiple memory nodes that utilize atoms for generation, storage and processing of quantum states are connected by single-photon transmission in optical fibres1, 2. One promising avenue for the realization of quantum networks involves the manipulation of quantum pulses of light in optically dense atomic ensembles using electromagnetically ...

Abstract

A four-level N scheme with a two-mode active Raman gain core is investigated for large and rapidly responding Kerr effect enhancement at room temperature. The new scheme is fundamentally different from the electromagnetically induced transparency (EIT-)based ultraslow-wave Kerr effect enhancement scheme. It eliminates the requirement of group velocity matching and multispecies medium. It also eliminates significant probe field attenuation or distortion associated with weakly driven EIT-based schemes. We show that a probe field can acquire a large, frequency tunable, gain-assisted nonlinear ...

Abstract

A circularly polarized plane-wave is known to have no angular momentum when examined through Maxwell’s equations. This, however, contradicts the experimentally observed facts, where finite segments of plane waves are known to be capable of imparting angular momentum to birefringent platelets. Using a superposition of four plane-waves propagating at slightly different angles to a common direction, we derive an expression for the angular momentum density of a single plane-wave in the limit when the propagation directions of the four beams come ...

Abstract

Radiation pressure measurements on mirrors submerged in dielectric liquids have consistently shown an effective Minkowski momentum for the photons within the liquid. Using an exact theoretical calculation based on Maxwell’s equations and the Lorentz law of force, we demonstrate that this result is a consequence of the fact that conventional mirrors impart, upon reflection, a 180° phase shift to the incident beam of light. If the mirror is designed to impart a different phase, then the effective momentum will turn out ...

Abstract

We examine the force of the electromagnetic radiation on linear, isotropic, homogeneous media specified in terms of their permittivity ε and permeability μ . A formula is proposed for the electromagnetic Lorentz force on the magnetization M, which is treated here as an Amperian current loop. Using the proposed formula, we demonstrate conservation of momentum in several cases that are amenable to rigorous analysis based on the classical Maxwell equations, the Lorentz law of force, and the constitutive relations. Our analysis ...

Abstract

It is shown that in a moving, lossless, dispersive dielectric, the group velocity is distinct from the energy velocity defined as the ratio of the Poynting vector and the energy density. The total energy flux is equal to the product of the total energy density and the group velocity. It consists of the electromagnetic flux represented by the Poynting vector and the particle energy flux associated with the motion of particles in the medium. Only the group velocity is shown to ...

Abstract

The Poynting vector; energy density; and energy velocity of light pulses propagating in an anomalous dispersion medium with two closely spaced gain lines are calculated. The results show that a negative energy density in the medium propagates along the opposite direction of incidence with a velocity similar to the negative group velocity v g while Poynting vector is in the same direction of incidence. In other words; one might say that a positive energy density in the medium would propagate along ...

Abstract

We derive the force of the electromagnetic radiation on material objects by a direct application of the Lorentz law of classical electrodynamics. The derivation is straightforward in the case of solid metals and solid dielectrics, where the mass density and the optical constants of the media are assumed to remain unchanged under internal and external pressures, and where material flow and deformation can be ignored. For metallic mirrors, we separate the contribution to the radiation pressure of the electrical charge density ...