Research On Fabrication Technology Of Aspherical Bifocal Microlens

Laser diode has been widely used because of numerous advantages. However, with its poor beam quality, beam shaping is usually required to meet the requirements of use. In this paper, a method using aspherical bifocal microlens to collimate beam is proposed.The research work is present as following:(1) The beam characteristics of laser diode is analyzed, and the astigmatism of laser beam is calculated. Based on the characteristics of the astigmatism beam, a method that can simultaneously collimate the fast axis and slow axis of the beam with aspherical bifocal microlens is proposed. The surface type of microlens is calculated, and the simulation of the beam collimation with aspherical bifocal microlens is conducted using ZEMAX.(2) Bifocal microlens was fabricated by melting photoresist. A method that utilizes anisotropic groove type microstructure and droplet solidification method to fabricate aspherical bifocal microlens was proposed. The thermodynamic analysis on microstructure changing contact angle was made. The microstructure was fabricated with ICP etching, and the experiments of contact angle to verify the wetting law were done.(3) Groove type microstructure was fabricated on the basement, on which aspherical bifocal microlens was manufactured by droplet solidification method. Some parameters of microlens were measured, including radius of curvature, aspheric coefficient and the focal length. The experiment of beam collimation was done with the aspherical bifocal microlens.This paper, from the perspective of both theoretical analysis and experiment, studies the fabrication technology of aspherical bifocal microlens. Bifocal microlens was fabricated and the experiment of beam collimation was done. The experimental results shows that beam collimation effect of bifocal lenses with hyperboloid is better.