Wave Optics

This chapter discusses wave optics, pertaining to the physics of light, including interference and diffraction. Light is a form of energy that radiates electromagnetic energy. It propagates in a straight line as a transverse wave at a speed of 2.99792458 m/s in a vacuum. In other media, its speed is less than this value. The wavelength of visible light lies between 380 nm and 750 nm. Particle theory, wave theory, and the modern quantum theory of light have been introduced. This follows the superposition principle and Huygen's principle. Concepts and types of the phenomenon of interference have been introduced, highlighting the importance and applications of Newton's ring and the Michelson interferometer. Diffraction of light is the phenomenon whereby light waves bend or disperse when they traverse an aperture or encounter an obstruction with dimensions comparable to wavelength of light. A detailed explanation of the Fraunhofer diffraction due to a single slit, circular aperture, and grating has been provided. Resolving power and Rayleigh's criterion for resolution appear as the concluding topics of the chapter.