Sol−Gel Replication of Microoptical Elements and Arrays

Abstract

Facile replication of microoptical elements and arrays was performed in sol-gel matrixes prepared by the fast sol-gel method. These sol-gel resins, made from mixtures of alkylalkoxysilane monomers, undergo hydrolysis and polymerization within 10-20 min and curing within a few days. Single-step reproducible fabrication of large crack-free elements of 1 cm thickness and up to 10 cm in diameter was demonstrated. High accuracy of replication was facilitated by maintaining a very small shrinkage of only a few percent during the curing stage. This was attained by removing most of the volatile products from the sol, without gelling, prior to casting it onto the template. Accurate replication depends on adequate control of two key parameters: the replica-template adhesion-separation timing, by manipulating the template surface via oxidative etching, and the drying-cross-linking relative pace, by accurately tailoring the silanes mixture, the water-to-silane ratio, and their hydrolysis and polymerization.

Negative dielectric loss phenomenon in porous sol–gel glasses

“…The following sol-gel materials obtained by using different catalysts were chosen for investigation: (i) five sol-gel glasses prepared by the regular way and (ii) four fast solgel glasses produced via the fast sol-gel route [8].…”

Sol‐gel derived C‐SiC composites for re‐entry structures

“…Resin Fabrication: The chemicals and preparation procedure involved in fabricating the fast-sol-gel-derived resins are described in detail elsewhere [1][2]. The general procedure comprises (1) admixing of methyltrimethoxy-silane (MTMS) with 0-30 % of tetramethylortho-silicate (TMOS) and dimethyldimethoxysilane (DMDMS); (2) rapid addition of aqueous HCl (5*10 -3 M) or HF (1-5 M), adjusted so that 1.5 moles water are added per each mole silane; (3) 10 min stirring (sealed reaction bottle) at 100 C followed by gradual opening the reaction bottle (during ca.…”

“…It allows facile fabrication of siloxane-backbone glassy materials within min-utes of reaction and a few hours of curing at temperatures of 65-140 o C. These glassy materials are tailorable to a wide variety of specific objectives, monoliths, composites, coatings, sealants, and micro-optical elements and arrays. Coatings made from such resins readily adhere to most surfaces and form chemical bonds with oxide-covered ones [2].…”

Hybrid materials for optics and photonics

“…Sol-gel processing has been shown, in general, to be well adapted for fabrication of several types of micro-optic elements [203][204][205] such as diffraction gratings, 206 Fresnel lenses 207 and microlens arrays. Microlens arrays, in particular, are formed by multiple lenses which are aligned on a supporting substrate and are used in photonics for the optical interconnections between optical fibers and light-emitting or detecting devices.…”