This is the first episode about coherence and how this wave phenomenon can cause waves to behave like localized entities or energy quanta.
Unfortunately the quantum (or corpuscular...
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This is the first episode about coherence and how this wave phenomenon can cause waves to behave like localized entities or energy quanta.
Unfortunately the quantum (or corpuscular) description of light leads to a lot of confusion (and nonsense). The goal of this video is to describe "quantized" behavior of light purely from wave principles. Because: why first transform waves into particles and then try to describe them using a wave function?
Contents:
0:00 Intro
1:04 Historical perspective
2:58 Quantization and the photoelectric effect
6:42 Light is just waves
7:24 Coherence explained
12:54 Temporal coherence as a sum of EM-fields
16:47 Coherence length vs. spectral band width
20:25 experiments on the coherence length of light
Link to the referenced Physics Explained video:
https://www.youtube.com/watch?v=FRP4AqZR3UU
A sharp viewer noted that there is an error in the formula on the sheet at 27:25 : The product of delta time and delta energy in the Heisenberg uncertainty principle is not equal to (h*4*pi) but h/(4*pi), so a much smaller value. This also makes the value of delta frequency times delta time 1/(4*pi) not 4*pi Unfortunately I did not double check the values. Thanks for pointing this out Steve.
In this video short clips of other YouTube channels were used for illustration. Because of their short length and purpose, they are to be considered to be "fair use".
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Did I forget anyone? Please let me know and I'll set things straight.
