title: Fabrication of concave refractive microlens arrays in solgel glass by a simple proximity-effect-assisted reflow technique.
abstract: We report a simple method for fabricating a concave refractive microlens array (MLA) in solgel glass by using a proximity-effect-assisted reflow technique. The solgel concave refractive MLA that we fabricated had excellent surface smoothness; good dimensional conformity, with an 8.23% nonuniformity of the microlens elements; and structural perfection, with a biggest deviation of 1% from a perfect concave spherical crown. The relative error between the measured and the designed values of the concave MLA's focal length was only 1.83%. Compared with the conventional fabrication techniques for concave MLAs, the proposed method has significant advantages including simplicity, low cost, good element conformity, and smooth device surface.
authors.affiliation: Photonics Research Centre, School of Electrical & Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798.
authors.forename: Miao
authors.initials: M
authors.lastname: He
authors.forename: Xiaocong
authors.initials: X
authors.lastname: Yuan
authors.forename: Jing
authors.initials: J
authors.lastname: Bu
authors.forename: Wai Chye
authors.initials: WC
authors.lastname: Cheong