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# Photon Source

Gated photon source starts with the bright green 532nm wavelength laser beam that strikes a crystal (bright green spot, center) and is converted into pairs of photons at 810nm (false colored blue here, it's at the end of the red spectrum) and 1550nm (in the infrared, false colored red here.). The "blue" beam is the herald channel, the "red" beam goes through a spool of optical fiber (right) to delay it long enough for the gate to open or shut.

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January 19, 2011

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