Fabrication of a Chalcogenide Glass Microlens Array for Infrared Laser Beam Homogenization.

Fan Zhang,Hao Bian,Minjing Li,Feng Chen,Qing Yang,Shaokun Wang,Xun Hou

doi:10.3390/ma14205952

Abstract

Infrared (IR) microlens arrays (MLA) have attracted increasing interest for use in infrared micro-optical devices and systems. However, the beam homogenization of IR laser light is relatively difficult to achieve because most materials absorb strongly in the IR wavelength band. In this paper, we present a new method for the application of double-sided quasi-periodic chalcogenide glass (ChG) MLAs to infrared laser homogenization systems. These are non-regular arrays of closely spaced MLAs. The double-sided MLAs were successfully prepared on the ChG surface using a single-pulse femtosecond laser-assisted chemical etching technique and a precision glass molding technique. More than two million close-packed microlenses on the ChG surface were successfully fabricated within 200 min. By taking advantage of ChG’s good optical performance and transmittance (60%) in the infrared wavelength band (1~11 μm), the homogenization of the IR beam was successfully achieved using the ChG quasi-periodic MLA.

Highlights

With the development of infrared technology, infrared lasers have been gradually applied in various fields, such as atmospheric monitoring [1], remote sensing [2], night vision systems [3], IR countermeasures [4], and medical applications [5]
microlens arrays (MLA) were prepared using femtosecond laser wet etching combined with a precision
chalcogenide glass (ChG) MLAs were prepared using femtosecond laser wet etching combined with a precimolding technique and successfully applied to achieve the homogenization of infrared sion molding technique and successfully applied to achieve the homogenization of infralasers

Summary

Introduction

With the development of infrared technology, infrared lasers have been gradually applied in various fields, such as atmospheric monitoring [1], remote sensing [2], night vision systems [3], IR countermeasures [4], and medical applications [5]. Various methods can be used to realize laser beam homogenization, such as diffractive optics, aspherical lens systems, polygonal light tubes, liquid crystal spatial modulators, and MLAs [10,11,12,13,14]. With advantages such as their simple structure, low transmission loss, high damage threshold, and low requirements for incident light intensity distribution, MLAs are widely used optical elements for laser beam homogenization [15,16,17]. A solution is proposed to reduce the interference fringe contrast by perturbing the spatial distribution of the microlenses using a double-sided non-periodically arranged MLA

Methods

Findings

Discussion

Conclusion