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Tuesday, January 11, 2011

optics and light representation

Well, in accordance with this blog title, I move slowly, and as I noted recently, have been moving into the radiation end of things. Its somewhat of a shock to go from such a specialized literature of accelerator physics and beam physics to the extremely vast literature of optics and light.
On the other hand, accelerator physics was never such a well defined concept. It is well defined from the sense that it is a collection of all the physics one may need in analyzing, building, designing or improving a particle accelerator. But its a rather mixed bag of classical mechanics, relativity, electricity and magnetism, and material science.

On to radiation, one has Maxwell's equations describing the evolution of electric and magnetic fields. However, one often represents light via a complex scalar field, or via a Wigner function, when coherence properties are required. Currently I'm trying to understand all this terminology related to Fourier Optics. One has a point spread function. One has an optical transfer function. One has an amplitude transfer function. Does one gain something new with these different representations? With the Wigner function, there's a partial interpretation in terms of the distribution of photons. But, being sometimes negative, its not such a clear interpretation. There are operator representations for quantum optics. One has the coherent states and the squeezed states. Is all of this unified, or in each domain of application does one in some sense use a different representation and mapping between the the real physical system and our calculational tools?

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