Quantum Optics by Scully and Zubairy
Theoretical chemists think light as semiclassical in the sense that the quantum nature of light is not affecting chemistry. Technically speaking, the light field comes into play in the basic equation to describe chemistry, time-dependent Schodinger equation, as an external time-dependent parameters. However, light is quantum mechanical in nature. And with the advent of nonclassical light realized in labrarotory, it is essential to go beyond the semiclassical view and take a full quantum mechanical treatment of light.
If you are interested in a deep understanding of light, the book “Quantum Optics” by Scully and Zubairy is an excellent book that gives a comprehensive introduction to the quantum mechanical properties of light. The prerequisite, in my opinion, is familiarity with basic quantum mechanics.