Ray Optics Simulation

Ray Optics describes light propagation in terms of “rays” and is commonly concerned with how light is propagated, reflected, and refracted and the formation of images. The “ray” in geometric optics is an abstraction, or “instrument”, which can be used to approximately model how the light will travel. Light rays are defined to propagate in a straight path as they travel in a homogeneous medium. Deviations occur at boundaries between media of different refractive index or if the index varies in space.

Ray Optics provides rules, which may depend on the color (wavelength) of the ray (or light), for propagating these rays through an optical system.

Fermat discovered a way to explain reflection and refraction as the consequence of one single principle  –  Fermat’s Principle: “Light propagating between two points follows a path, or paths, for which the time taken is an extremum. 

Fermat’s principle materialized into two laws 

• Law of reflection – the angle of incidence is equal to the angle of reflection
• Law of refraction – Snell’s law – formula used to describe the relationship between the angles of incidence and refraction

The path of light indicated by a ray can be plotted using Fermat’s Principle or its more useful form as Snell’s laws. This allows us to locate images of objects formed when light travels through complicated lens systems or, in the case of mirages, through a medium of spatially varying refractive index.