Wavefront

• A wavefront is a conceptual tool used in the study of waves, including electromagnetic waves like light. It refers to the locus of all points that are in phase with each other along the wave at a given instant. In other words, it represents the leading edge of a wave as it propagates through a medium.
  • Sources that emit light in all directions, known as point sources, generate spherical wavefronts.
  • Lasers, which produce a narrow beam of parallel rays, create waves with flat wavefronts.
  • An electromagnetic wave with a flat wavefront is known as a plane wave.
• In addition to plane waves and spherical waves, there are also cylindrical waves which are produced when a point source is extended along a straight line.
• The shape of the wavefront can be influenced by interaction with different mediums or obstacles, such as when:
  • Refraction causes the path of light to bend as it crosses the boundary between two transparent media.
  • Dispersion causes light to separate into its constituent wavelengths, each of which bends to a different degree as it crosses the boundary between two transparent media.
  • Diffraction causes light to bend around the edges of obstacles into regions that would otherwise be in shadow.
• The concept of wavefronts applies not only to light but also to other types of waves such as sound waves or water waves.

More about wavefronts

• Wavefronts are typically used to describe the behaviour of waves in classical physics, where waves exhibit properties such as interference, diffraction, and refraction.
• While wavefronts are often associated with the behaviour of light, which can exhibit both wave-like and particle-like properties, they are a description of the wave nature of light rather than individual photons.
• At the quantum level, the behaviour of individual photons is described differently, often using concepts such as wave functions in quantum mechanics.