Lens-on-lens microstructures

Abstract

Microlenses with multiple focal lengths play an important role in three-dimensional imaging and the real-time detection of unconfined or fluctuating targets. In this Letter, we present a novel method of fabricating lens-on-lens microstructures (LLMs) using a two-step femtosecond laser wet etching process. A 3×3 LLM array was made with a diameter of 129.0 μm. The fabricated LLM has two focal lengths, 80.4 and 188.7 μm, showing excellent two-level focusing and imaging abilities. Its size and focal length can be controlled by adjusting laser power and etching time. Its surface roughness remains about 61 nm. This simple and efficient method for large-scale production of LLMs has potential applications in diverse optical systems.

A Review of Femtosecond‐Laser‐Induced Underwater Superoleophobic Surfaces

“…Lens is one of the most basic optical components, which is widely applied in light convergence and divergence, imaging, photography, optical microscopy, and optical communication . Femtosecond laser microfabrication has been very successful in fabricating various microlens arrays . For example, Chen et al develops a technology named “femtosecond laser wet etching” and have prepared different microlens structure on the silica glass, K9 glass, and silicon surfaces .…”

“…Femtosecond laser microfabrication has been very successful in fabricating various microlens arrays . For example, Chen et al develops a technology named “femtosecond laser wet etching” and have prepared different microlens structure on the silica glass, K9 glass, and silicon surfaces . The sample surface is first irradiated by femtosecond laser pulses through a point‐by‐point process to generate a series of separated microholes on the surface.…”

Rapid optical μ-printing of polymer top-lensed microlens array

“…A microlens with two aspheric surfaces was fabricated to achieve a diffraction-limited focus spot for high-density optical storage systems [4]. Particularly, a special kind of microlenses with lens-on-lens structures has attracted remarkable attention because of its extraordinary beam reshaping abilities as well as the promising applications in diverse optical systems, such as optical storage and unconfined fluctuating target counting systems [5][6][7][8][9][10].…”

Fabrication of Micro-Optics Elements with Arbitrary Surface Profiles Based on One-Step Maskless Grayscale Lithography

“…Electron-beam lithography [ 6 , 7 ] and focused-ion beam [ 8 ] can realize a high-resolution fabrication of the structure with complicated surface profiles in principle, but require a long-term and expensive device. The direct laser writing technique [ 9 , 10 , 11 ] is a promising and economic method for the fabrication of microstructures, but the scanning mode will limit the improvement of work efficiency. The thermal reflow method [ 12 , 13 , 14 ] cooperated with conventional binary lithography is usually applied for micro lens array’s generation efficiently, but this method is difficult to control the surface profile precisely.…”