What describes the path of a single photon of light?

The concept of a single photon of light can be well described by the term "ray." In optics, a ray refers to the straight-line path that light travels, which is often used in ray optics to simplify the understanding of how light interacts with various media, such as lenses and mirrors. This concept is crucial when discussing how light behaves in systems where it can be reflected, refracted, or absorbed.

While a ray provides a useful representation of the direction of a single photon, it is important to note that other terms may also apply in different contexts. For example, a wave function typically describes the quantum state of a particle, which is broader and not specific to the path of light. Trajectory could imply a more specific path taken through space and may not necessarily reflect the unique properties of light, especially when considering its behavior as both a wave and a particle. Particulate motion suggests a classical particle behavior, which doesn’t encapsulate the full wave-particle duality of light.

Thus, defining the path of a single photon as a ray helps to clarify its behavior in practical optics, allowing for an easier understanding of light propagation.