Frustrated total internal reflection of newton rings multiple beam interference

Abstract

Frustrated Total Internal Reflection FTIR phenomenon is manifested employing Newton‟s rings setup generated via a coherent light beam of a laser diode ( . All concentric bright and dark rings, except the central bright spot, were noticed to recede (disappear) when the incident angle exceeded the critical angle of 41o. It was also shown that the current setup has proven its applicability for other tests and can give convenient results that conform with theory. Neither the concept nor the design is beyond what can be realized in an undergraduate laboratory. However, technical improvements in mounting the prism - lens may be advisable. As an extension of the experiments, the effect can be studied using hollow prism filled with liquids of different refractive indices for both S and P polarizations of light. Also, the relationship of wavelength on the penetration depth can be explored.

Keywords

• Frustrated total internal reflection, evanescent waves, total internal reflection, newton rings, multiple – beam interference.