Interferometry: Refraction Index and Applications

This lecture delves into the measurement of air's refractive index, exploring how introducing different refractive indices in an interferometer affects interference patterns. The instructor discusses the impact of changing the refractive index on wavelength, periodicity, and interference visibility. Various interferometer types, such as Michelson and Sagnac, are explained, along with their applications in precision measurements and optical communication. The lecture also covers lithography using interference patterns to create nanostructures, emphasizing the importance of coherence length in interference phenomena. Practical examples, like using white light for interference and adjusting interferometers for optimal results, are demonstrated. The session concludes with a hands-on experiment showcasing interference patterns with different colored filters.