3 ms·
Temporal smear is caused by the varying refeactive index of glass with wavelength and the fact that a short time pulse must have finite (large) spectral width (
by hyeonwho4 8y ago
Temporal smear is caused by the varying refeactive index of glass with wavelength and the fact that a short time pulse must have finite (large) spectral width (by the uncertainty principle), not by the bouncing.
- kazinator 8y agoSo, the different path lengths implied by internal reflections don't contribute anything to the smear? By the way, the uncertainty principle doesn't say we can't have a narrow pulse. Frequency versus time can be used as an analogy to help explain the uncertainty principle. If we know a precise frequency, the signal is poorly localized in the time domain. If a signal is narrowly localized in the time domain, it is poorly localized in the frequency domain. The uncertainty principle is something else, though: it revolves around not being able to make certain related measurements simultaneously, at the quantum level. We can be quite certain about the frequency content of a transient pulse and its exact temporal shape, if it's not something from the quantum domain.