High magnification polymeric lens for smartphone microscope

Abstract

In this work, we present a facile method for fabrication of plano-convex lenses, using high reflective optical polymer (Polydimethylsiloxane, Sylgard 184 by Dow Corning, n ~1.42 and Norland Optical adhesive 61, NOA61 by Norland Products, ~1.56) under the confined sessile drop technique. The confined sessile drop technique is a facile method and an adjustable lens geometry through controlled the weight of liquid polymer on the lens substrate, as PMMA circular disk and Sylgard circular disk, with different diameter (2.5-6.0 mm). The liquid polymer was gradually spread and radially over the surface of the lens substrate, and resistance to spreading of liquid by a sharp edge under the gravitational force and interfacial surface tension to form spherical cap with smooth surface. When the use of the weight of liquid polymer increased, the deformation of the lens observed due to affect the gravitational force. The fabricated lenses, as Sylgard 184 plano-convex lens and NOA 61 plano-convex lens, provides the magnification up to 51.0X and 88.3X, respectively. In addition, the imaging quality of the fabricated lenses was characterized using USAF 1951 target. The fabricated plano-convex lenses which could be used to convert a smartphone to a smartphone microscope to taken the small objects that cannot see by naked eye. Due to high refractive index of NOA 61 plano-convex lens, it can be utilized as design of low cost SPR sensors under Kretschmann surface plasmon sensors configuration through deposited with 50 nm-Au film on rough surface as base of NOA 61 plano-convex lenses.