Demonstration of synergic Fresnel and Fraunhofer diffraction for application to micrograting fabrication. (October 2020)

• Record Type: Journal Article
• Authors: Shetty, Pritam P.; Bingi, Jayachandra
• Is Part Of: Optics & laser technology. Volume 130(2020)
• Publication Date: 2020-10
• Subjects: Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2020.106340
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: Paper demonstrates the novel compound diffraction (Fresnel together with Fraunhofer) for the first time and study. Variable Hermit Gaussian beam intensity patterns are realized both in simulation and experiment. Achieved the synergic diffraction and vertical fringes in the case of laser speckles. Same phenomena successfully implemented in speckle lithography and fabricated high quality micro gratings. Pitch variability of micro-grating is also demonstrated. Abstract: Diffraction is a manifestation of light at edge due to its wavelike nature. The well-known diffraction phenomena are Fresnel and Fraunhofer, they find variety of applications individually. But the synergy of two phenomena is not studied and understood, which is important to understand the compound optical instruments. This research studies and demonstrates the synergic patterns of Fresnel and Fraunhofer diffractions. The combined diffraction resulted in the patterns like Hermite-Gaussian Beam intensity distribution in both simulated and experimental results. Further, the combined phenomenon is implemented in speckle lithography to fabricate wide area micro grating patterns which are better than simple speckle diffraction grating patterns. This work may contribute to the deeper understanding of complex diffraction in optical instruments and shows the way for robust fabrication of micro gratings.