Wave Optics Fundamentals

Wave Optics

• Wavefront: The locus of all points in a wave that are in the same phase.

• Types of wavefronts:

  • Spherical: Produced by a point light source. Examples include light bulbs.
  • Cylindrical: Produced by a linear or rectangular light source. Examples include tube lights.
  • Plane: Produced by a point source at a very large distance, or a linear source at significant distance from the wavefront being observed. Examples include distant stars or lights far away.

• Huygen's Principle: Each point on a wavefront acts as a source of secondary wavelets. The new wavefront is the envelope of these wavelets.

• Reflection (using wave theory):

  • Incident ray, reflected ray, and normal all lie in the same plane.
  • Angle of incidence equals angle of reflection.

• Refraction (using wave theory):

  • The emergent wavefront travels at a changed angle and speed.
  • Snell's Law describes the relationship between angles of incidence and refraction, along with the refractive indices of the two mediums.

• Interference: The redistribution of light energy when two or more light sources overlap.

  • Conditions for sustained interference:

    • Coherent sources of light
    • Sources need to be close to each other

  • Types of Interference:

    • Constructive: When the crests of two waves overlap, resulting in a larger amplitude and greater intensity.
    • Destructive: When the crest of one wave overlaps the trough of another, resulting in a smaller amplitude and decreased intensity.

• Coherent Sources: Two or more sources that emit light waves with a constant phase difference.

• Young's Double Slit Experiment: A demonstration of interference using coherent light sources.

• Diffraction: Bending of light around obstacles.

  • Types of Diffraction:
    • Fresnel
    • Fraunhofer

• Polarisation: Restriction of light waves to vibrate in a specific plane.

  • Unpolarized light: Vibrates in all planes perpendicular to the direction of propagation.
  • Polarized light: Vibrates in a single plane.
  • Polarization by Reflection: The phenomenon where reflected light becomes polarized when incident light strikes a surface at a specific angle (Brewster's angle).

Explore key concepts in wave optics, including wavefront types, Huygen's Principle, reflection, and refraction. This quiz will challenge your understanding of how light behaves in different scenarios. Test your knowledge of these fundamental principles of physics.