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03-30-2015, 11:09 PM #1
 Class 2 Laser Join Date: Dec 2013 Location: Dallas, TX Posts: 288 Rep Power: 59111
Class 2 Laser

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A laser pulse so fast.....

that only one photon is fired! WTW? It allows scientists to entangle 30 times the current record of entangled atoms!

http://finance.yahoo.com/news/mit-sc...194735125.html

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03-31-2015, 06:13 AM #2
 Class 4 Laser Join Date: Sep 2007 Location: Wisconsin Posts: 9,292 Rep Power: 199036
Cyparagon
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Re: A laser pulse so fast.....

Physics time

E=hc/λ with hc being planck's constant times the speed of light. If we pick a wavelength 650nm, the pulse energy of a single photon is 1.986*10^-25/(650*10^-9) = 306 zeptoJoules (and I had to look up which prefix to use). To put that into perspective, you could fire 10 billion of these pulses per second, and the average power would still be FAR less than a billionth of a milliwatt.

The pulse length would be λ/c = 650*10^-9/(299792458) = 2 femtoseconds.

Femtosecond lasers have existed for quite some time already, and in powers far, FAR greater than zeptoJoules. It's a good article, but the entanglement is the story here, not the laser.
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Last edited by Cyparagon; 03-31-2015 at 06:16 AM.

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