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Observación de la propagación del pulso hacia atrás a través de un medio con una velocidad de grupo negativa

George M Gehring¹, Aaron Schweinsberg, Christopher Barsi

¹Institute of Optics, University of Rochester, Rochester, NY 14627, USA. gehring@optics.rochester.edu

Science (New York, N.Y.)

|May 13, 2006

Resumen

Los pulsos parecen viajar hacia atrás en materiales con velocidad de grupo negativa. Sin embargo, este estudio muestra que mientras el pico de pulso se mueve hacia atrás, la energía siempre fluye hacia adelante en las fibras ópticas.

Área de la Ciencia:

* Física es la física.
* La óptica es la óptica.
* Ciencias de los materiales Ciencia de los materiales.

Sus antecedentes:

* La propagación de los pulsos de luz en materiales con velocidad de grupo negativa no se entiende bien.
* Modelos teóricos simples sugieren la propagación del pulso hacia atrás, creando una paradoja con el flujo de energía.

Objetivo del estudio:

* Para investigar el comportamiento de los pulsos ópticos en un material que exhibe velocidad de grupo negativa.
* Para verificar experimentalmente la dirección de propagación del pico de pulso frente al flujo de energía.

Principales métodos:

* Utilizó una fibra óptica dopada con erbio como medio material.
* Se midió la evolución temporal de la intensidad del pulso en múltiples puntos a lo largo de la fibra.

Principales resultados:

* Se demostró que el pico del pulso óptico se propaga hacia atrás dentro de la fibra.
* Confirmado que el flujo de energía se mueve constantemente en dirección hacia adelante, a pesar del movimiento de pico hacia atrás.

Conclusiones:

* Los resultados experimentales resuelven la paradoja de la propagación del pulso hacia atrás en materiales de velocidad de grupo negativo.
* Esta investigación aclara que el movimiento hacia atrás de los picos no implica un transporte de energía invertido.

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