I am looking for a nice book or online course treating in a rigorous way the quantization of the E.M field.
My needs in the end are to do quantum optics, but I would like to see the proof in a nice way. Indeed in the books I have read, they basically show that the Hamiltonian is a sum of harmonic oscillators, and then quantize each mode.
But I am more interested in a rigorous derivation with the Lagrangian, using the canonical quantization.
Where can I find such resource ?