pl. explain light theory and wave theory

first of all the light theory

quantum theory of light, the idea that light exists as tiny packets, or particles, which he called photons. Alongside Max Planck's work on quanta of heat Einstein proposed one of the most shocking idea in twentieth century physics: we live in a quantum universe, one built out of tiny, discrete chunks of energy and matter.

on the further basis we got that Newton also used the publication of Opticks to defend his stance on diffraction, in order to do so he had to appeal to wave-like properties and argued that particles of light create waves in the aether.