By carefully controlling the distance between the mirrors, the photons or light waves being emitted by many excitons can be made to build in intensity and resonate with one another, like the vibrations of a vigorously bowed violin string.
This creates yet more excitons which produce more resonant light waves and so on, until energy begins to cycle between light and matter so fast - in just a few trillionths of a second - that according to the rules of quantum physics it becomes impossible to tell in which of the two states it is stored. And that is a polariton. http://www.newscientist.com/article/mg20227031.500-quantum-lasers-half-light-half-matter.html The gestation of polaritons is a complex process. It begins in a sandwich of semiconducting materials known as a quantum well. Electrons are jammed tightly into the thin, sheet-like filling of this sandwich - typically less than a micrometre thick - and so are particularly excitable. Add a little drop of energy, in the form of light or a voltage, and some of the electrons absorb it and jump to a higher energy level, leaving behind an absence of electrons - positively-charged "holes". An electron-and-hole pairing is called an exciton, and is usually a short-lived affair: the energised electron soon gives up its extra energy and plonks itself back into the hole. At the same time it releases the energy it had taken on board, in the form of a photon of light. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Hum Sufferers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/hum-sufferers?hl=en -~----------~----~----~----~------~----~------~--~---
