optics

Optics is the branch of physics that studies the behavior and properties of light — electromagnetic radiation across a range of wavelengths — and its interactions with matter. It carves out a domain delimited by its subject (light and its phenomena: reflection, refraction, diffraction, interference, polarization, dispersion) and its methods (ray tracing, wave optics, quantum optics), distinguishing it from adjacent fields like photonics (which emphasizes engineered light-based technologies) and acoustics (which studies mechanical waves). Optics persists through mathematical formalisms (Maxwell's equations, Fermat's principle), instrumental traditions (lenses, mirrors, spectrometers), and pedagogical structures (textbooks, laboratory curricula, professional societies). [formal: optica | substrate: mind | horizon: centuries | explicit: yes | epoch: 0.01]