title: Fabrication of highly uniform and porous MgF2 anti-reflective coatings by polymer-based sol-gel processing on large-area glass substrates.
abstract: Despite recent progress in the fabrication of magnesium fluoride (MgF2) anti-reflective coatings (ARCs), simple, effective and scalable sol-gel fabrication of MgF2 ARCs for large-area glass substrates has prospective application in various optoelectronic devices. In this paper, a polymer-based sol-gel route was devised to fabricate highly uniform and porous MgF2 ARCs on large-area glass substrates. A sol-gel precursor made of polyvinyl acetate and magnesium trifluoroacetate assisted in the formation of uniformly mesoporous MgF2 ARCs on glass substrates, leading to the attainment of a refractive index of ~1.23. Systematic optimization of the thickness of the ARC in the sub-wavelength regime led to achieving ~99.4% transmittance in the case of the porous MgF2 ARC glass. Precise control of the thickness of porous MgF2 ARC glass also resulted in a mere ~0.1% reflection, virtually eliminating reflection off the glass surface at the target wavelength. Further manipulation of the thickness of the ARC on either side of the glass substrate led to the fabrication of relatively broadband, porous MgF2 ARC glass.
authors.affiliation: Department of Mechanical Engineering, National University of Singapore, Singapore 117574, Republic of Singapore. Centre for Nanofibres and Nanotechnology, National University of Singapore, Nanoscience and Nanotechnology Initiative, 2 Engineering Drive 3, Singapore 117576, Republic of Singapore. Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Republic of Singapore.
authors.forename: Hemant Kumar
authors.initials: HK
authors.lastname: Raut
authors.forename: Saman Safari
authors.initials: SS
authors.lastname: Dinachali
authors.forename: Kwadwo Konadu
authors.initials: KK
authors.lastname: Ansah-Antwi
authors.forename: V Anand
authors.initials: VA
authors.lastname: Ganesh
authors.forename: Seeram
authors.initials: S
authors.lastname: Ramakrishna