Open AccessFabrication of a compound infrared microlens array with ultrashort focal length using femtosecond laser-assisted wet etching and dual-beam pulsed laser deposition
Author(s) -
Chenglong Deng,
Hyeongwon Kim,
Hyungson Ki
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.028679
Subject(s) - microlens , materials science , optics , focal length , femtosecond , laser , optoelectronics , etching (microfabrication) , lens (geology) , fabrication , nanotechnology , layer (electronics) , medicine , physics , alternative medicine , pathology
We present the design, fabrication, and characterization of a compound infrared microlens array having an ultrashort focal length and a hyperbolic profile that comprises a PDMS microlens array and a GRIN lens. A concave microlens mold was first fabricated on a fused silica substrate using femtosecond laser irradiation followed by a wet etching process, and a standard replication process was employed to fabricate a PDMS convex lens array. To shorten the focal length further and cut off the visible spectrum of light, a graded DLC/silicon coating, which functioned as a GRIN lens and a visible light cut-off filter, was additionally deposited using dual-beam pulsed laser deposition. The lenslet diameter was 6 µm and the graded coating reduced the focal length from 4.5 to 2.9 µm.