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Blasting the photoelectric effect out of the quantum realm with a very intense light source


In 1905, Albert Einstein showed that the photoelectric effect—the ability of metals to produce an electric current when exposed to light—could be explained if light is quantum, traveling in discrete bundles of energy. His model, the photon theory, won him the Nobel Prize in 1921, but it left us with an enigma: why does the classical model of electric fields yield correct experimental results for some systems, but fail so dramatically for the photoelectric effect? In other words, at what point does the quantum world begin and the classical world end?


By directing very intense light to a nanoscale needle-like tip, G. Herink, D. R. Solli, M. Gulde, and C. Ropers have bridged the gap between the quantum and classical views of the photoelectric effect. The sheer number of photons hitting the needle dwarf the number of electrons involved, which ensures that individual photon interactions do not dominate. Instead, they created a quasi-classical system in which the bulk electric field of all the photons influences individual electrons. This result shows why the classical and quantum views are correct in certain regimes, and hints at an entirely new way to manipulate electrons in nanoscale materials.


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Lees verder: http://arstechnica.com/science/news/2012/0...ical-regime.ars


Bron: Ars Technica