It's difficult to attribute the "discovery" of light rays to a single individual because light has been observed and understood gradually over centuries. However, Christiaan Huygens made significant contributions to understanding light rays with his wave theory of light.
Huygens, a Dutch mathematician and astronomer, articulated the first detailed wave theory of light in his Traité de la Lumière (1690), which translates to "Treatise on Light". This theory provided a framework for understanding light's behavior, including reflection and refraction, based on the concept of light rays propagating as waves.
While not the "discoverer" in the sense of first observing light, Huygens' work was crucial in formalizing the understanding of light rays as a fundamental aspect of light's nature. Other scientists before him, like ancient Greek scholars, had speculated about the nature of light, but Huygens provided a mathematical and theoretical foundation.
In summary, while many people have contributed to our understanding of light, Christiaan Huygens is a key figure in the development of light ray theory due to his comprehensive wave theory of light which included the laws of reflection and refraction.
