Recently physicists have managed to build "attosecond lasers", lasers which emit pulses 10^-18 seconds long, interrupted by much longer periods of darkness (at least 10^-14 seconds). Before them, lasers emitting femtosecond (10^-15 seconds) pulses have been around. Assuming they produce visible light, what colour is it?

I'm no expert on how pulsed lasers work, so I am not sure about what happens in them at the photon level.  Your description certainly applies to solid-state and gas lasers (and maybe others).  But the method which restricts laser output to pulses can and does influence photon energy.  In fact, a fundamental principle of modern physics says that the spectrum has to be wide if the pulses are so short.  Can you now solve the problem?

Posted by vswitchs on 2006-10-12 02:30:53