Video Experimental Relacionado
Updated: Jul 7, 2026
11:08
Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
Propagación superluminal y lenta de la luz en un sólido a temperatura ambiente
Matthew S Bigelow1, Nick N Lepeshkin, Robert W Boyd
1Institute of Optics, University of Rochester, Rochester, NY 14627, USA. mbigs@optics.rochester.edu
Science (New York, N.Y.)
|July 12, 2003
Resumen
Los investigadores observaron la propagación superluminal y ultra lenta de la luz en los cristales de alexandrita. Este fenómeno, impulsado por iones de cromo, ofrece un método más simple para controlar la velocidad de la luz con potencial para diversas aplicaciones.
Área de la Ciencia:
- Óptica y Fotónica.
- Física de la materia condensada Física de la materia condensada
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- El control de la velocidad de la luz es crucial para las tecnologías ópticas avanzadas.
- Los cristales de alejandrita dopados con iones de cromo son conocidos por sus propiedades ópticas únicas.
Objetivo del estudio:
- Para investigar las velocidades de propagación de la luz en cristales de alexandrita a temperatura ambiente.
- Comprender los mecanismos detrás de la propagación de la luz superluminal y ultra lenta.
Principales métodos:
- Observación experimental de la propagación de la luz en un cristal de alexandrita.
- Medición de las velocidades de grupo utilizando técnicas especializadas.
- Análisis de las oscilaciones de población coherentes que involucran a iones de cromo.
Principales resultados:
- Se observó la propagación de la luz superluminal (velocidad negativa del grupo) y ultra lenta.
- Velocidades de grupo medidas que van desde 91 m/s hasta -800 m/s.
- Los fenómenos observados se atribuyen a los iones de cromo en los sitios de espejo e inversión.
Conclusiones:
- Los iones de cromo en los sitios de espejo inducen la propagación superluminal debido a la absorción saturable inversa.
- Los iones de cromo en los sitios de inversión causan una propagación ultra lenta a través de la absorción saturable convencional.
- Este método proporciona una técnica accesible para lograr índices de grupos grandes, adecuados para diversas aplicaciones.
Videos de Conceptos Relacionados
01:07Propagation of Waves
When a wave propagates from one medium to another, part of it may get reflected in the first medium, and part of it may get transmitted to the second medium. In such a case, the interface of the two mediums can be considered as a boundary that is neither fixed nor free.
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
00:51Speed of Sound in Solids and Liquids
Most solids and liquids are incompressible—their densities remain constant throughout. In the presence of an external force, the molecules tend to restore to their original positions, which is only possible because the constituents interact. The interactions help the constituents pass on information about external disturbances, like sound waves. Therefore, sound waves travel faster through these media. Compared to solids, the constituents in a liquid are less tightly bound. Thus, sound waves...
01:20Mechanisms of Heat Transfer II
In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...
01:17Radiation: Applications
The average temperature of Earth is the subject of much current discussion. Earth is in radiative contact with both the Sun and dark space; it receives almost all its energy from the radiation of the Sun and reflects some of it into outer space. Dark space is very cold, about 3 K, so Earth radiates energy into it. For instance, heat transfer occurs from soil and grasses, the rate of which can be so rapid that frost can occur on clear summer evenings, even in warm latitudes.
The average...
The average...
01:28Standing Waves in a Cavity
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
01:23Photoluminescence: Fluorescence and Phosphorescence
Photoluminescence is a process where a molecule absorbs light energy and re-emits it in the form of light. This phenomenon occurs when a substance absorbs photons, promoting its electrons to higher energy level excited states, followed by a relaxation process in which the electrons return to their original ground state energy levels and emit light. Photoluminescence is widely observed in various materials, including semiconductors, and organic and inorganic compounds.
A pair of electrons in a...
A pair of electrons in a...