Light is conceived as a self-propagating perturbation of the EM field. This may sound like a silly question, but has this perturbation actually been measured/observed? Or is it accepted as the most parsimonious option that matches the evidence we have? My guess is that it is impossible to directly measure the ripple made by light due to QM limitations. Is that correct? One reason I ask is that, if this perturbation has been observed and we are confident that light is such a thing [or at least manifests as such a thing], then it appears the most accurate way of portraying wave/particle duality is "Light is a wave that exhibits some of the behaviors we attribute to particles (in particular quantization)."