On a Method to Employ Newton’s Rings Concept to Determine Thickness of Thin Films

Abstract

Newton's Rings experiment is traditionally utilized to find radius curvature of a lens. We propose a method in which this same set up can be used to find the thickness of thin films. The working principle is interference. It is based on the fact that, the formation of bright and dark interference fringes is a measure of the thickness of the air film at that point. We present the experimental data. The results from the experiment are in agreement with results obtained through geometry. Further, a method to improvise conventional interference at air wedge experiment which is generally used to determine the thickness of thin films is suggested.

Ring-Patterned Perovskite Single Crystals Fabricated by the Combination of Rigid and Flexible Templates

“…Newton’s rings of a spherical-cap droplet are a series of concentric-ring patterns because of the interference of the light reflected on the top and the bottom interfaces of the droplet. The number of the interference rings changes with different heights of the droplets. − In order to control the pattern of the templates precisely, a digital simulation was established, and the key factors influencing the Newton’s ring pattern were analyzed systemically, such as the viscosity and density of the polymer solution, and the design of the silicon pillars. Using the polymer-coated rigid templates, various ring-patterned perovskite single crystals were fabricated, which showed very fast photoluminescence (PL) characteristics on changing the design of the silicon pillars and the parameters of the fabrication process or different selections of the coating polymer solution.…”

Ultraflat Graphene Oxide Membranes with Newton-Ring Prepared by Vortex Shear Field for Ion Sieving

“…Vortices are interesting phenomena in nature, ranging from tornadoes to tiny vortices caused by a water droplet, and even encompassing situations invisible to the naked eye. − A vortex lies in a dense region of vorticity termed the vortex core, and the linear velocity is proportional to the radius and a circumferential velocity of zero. , Owing to the rotational motion of the fluid, the pressure at the center of the vortex is greater than at the edges, causing heavier particles to spiral toward the center, leading to a concentration gradient across the vortex. , A radial gradient in GO thickness is formed using the vortex action in preparing GOMs, resulting in colorful Newton’s ring membranes. − Furthermore, the vortex shear force can alter the material structure, flatten GO wrinkles, and regulate interlayer spacing, leading to smooth and dense GO structures with enhanced stability. This novel approach provides a route for resolving the selectivity and permeability trade-off in separation and enables the fabrication of controllable interlayer-spaced vortex GO membranes (v-GOMs).…”