4 ms·
Fun fact: these laser pulses are so short they are no longer a single wavelength. They have a spectrum due to the uncertainty principle. And at this short of a
by killjoywashere 1y ago
Fun fact: these laser pulses are so short they are no longer a single wavelength. They have a spectrum due to the uncertainty principle. And at this short of a time scale, it’s pretty broad.
- callc 1y agoI might regret asking, but could you explain this? (At a physics 101 level)
- ziofill 1y agoTime and energy are “conjugated” quantities: the more one is sharp, the more the other one is broad (it’s the same concept as Fourier transforming a Gaussian: the more it’s peaked the more the transform is broad). In order for the time duration of the pulse to be so short, it must have a broad uncertainty in energy, which for light is the same as a wide spectrum of colors. That’s why it’s very tricky to find materials for mirrors and lenses when working with these short pulses: they must work well over a large range of frequencies. If they happen to absorb some more than others not only they would burn, but they would also change the temporal profile of the pulse.
- callc 1y agoThanks very much ziofill. Is this the same thing as the Heisenberg Uncertainty Principle? Or is there something else similar for time and energy?
- ziofill 1y agoYes, it's the same thing in the sense that even if you work with a single photon the same applies (if you want its wavefunction to be narrow in time, its energy uncertainty must be broad)