You would have to be more careful with that statement. It is a bit of a misnomer that quantum mechanics is inherently discrete and classical is not. There are p

You would have to be more careful with that statement. It is a bit of a misnomer that quantum mechanics is inherently discrete and classical is not. There are plenty of examples of continuous descriptions in quantum mechanics (e.g. an oscillator in the coherent state basis, which is an extremely commonly used model). And plenty of examples of discrete behavior in classical mechanics (modes of oscillation, standing waves, etc). In the case of light, most of the "discreteness" of the quantum description is already present in the classical case. More importantly, there is plenty of the continuous description left in the quantum model.