Maskless fabrication of concave microlens arrays on silica glasses by a femtosecond-laser-enhanced local wet etching method

Abstract

A simple and efficient technique for large-area manufacturing of concave microlens arrays (MLAs) on silica glasses with femtosecond (fs)-laser-enhanced chemical wet etching is demonstrated. By means of fs laser in situ irradiations followed by the hydrofluoric acid etching process, large area close-packed rectangular and hexagonal concave MLAs with diameters less than a hundred of micrometers are fabricated within a few hours. The fabricated MLAs exhibit excellent surface quality and uniformity. In contrast to the classic thermal reflow process, the presented technique is a maskless process and allows the flexible control of the size, shape and the packing pattern of the MLAs by adjusting the parameters such as the pulse energy, the number of shots and etching time.

Biomimetic Multiaperture Imaging Systems: A Review

“…The first step in the process involves forming ablation-induced craters with diameters of a few micrometers using 30 fs and 800 nm laser pulses at a repetition rate of 1 kHz. (27) After the craters are fabricated, the concave microlens array may be fabricated by treatment with hydrofluoric (HF) acid solution. From the concave microlens array, a transparent polymer microlens array can be molded.…”

Fabrication of Microlens Arrays with Well‐controlled Curvature by Liquid Trapping and Electrohydrodynamic Deformation in Microholes

“…[ 20 ] Using concave polymer MLAs as the masters, convex polymer MLAs were fabricated by micromolding in a vacuum as described above. …”

Fabrication of Concave Resist Patterns for the Use of Reversal Molds of High-Density Micro-Lens Arrays

“…For this reason, various fabrication methods of micro-lens arrays are also researched and developed very eagerly, and new methods are frequently proposed one after another. Representative methods are thermal reflow of resist or plastic materials [13,14], etching of glass or plastic materials [15,16], ink-jetting of lens materials [17,18], tracking of laser light [19,20], gray scale lithography [21,22], and embossing [23,24]. What fabrication method is appropriate depends on the applications or necessary lens parameters and sizes.…”