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?
(In reply to re(2): I see - I think
I had the same thought as gregg, in that a laser generally emits light of a certain wavelength. So that should be the wavelength that determines the color. But what is not clear to me is what color is the light if only a fraction of a wavelength is emitted?
Also, no one has responded to my "half square" comment: if the burst of light in ON long enough for light to travel 300 nm, then does this correspond to a wavelength of 300 nm or 600 nm? I say 600 nm which is actually ORANGE (I previously said red, from memory).
Posted by Larry
on 2006-10-12 20:49:55