Method for preparing quasi-periodic microlens array by wet etching with femtosecond laser

Abstract

Disclosed is a method for preparing quasi-periodic micro-lens arrays through femtosecond laser wet etching. The method comprises that the velocity of a target material moved by an accurate processing platform is controlled according to the individual average size of quasi-periodic micro lenses needed to be processed, femtosecond lasers act for one pulse on the target material surface at a fixed interval, and a light damage area is produced on the target material with the acting focus of each femtosecond laser pulse serving as a center; chemical corrosion is performed on the target material processed by the femtosecond lasers through a hydrofluoric acid solution with a volume concentration in a range of 1% to 10%, and ultrasonic water-bath heating is assisted; and the corroded target material is cleaned thoroughly in deionized water to obtain a template finished product of mass quasi-periodic micro-lens arrays. The method has the advantages of being high in efficiency, low in cost, controllable in micro-lens individual shape size and the like, and negative effects of air breakdown effects of laser focusing, periodic light field coupling stacking effects and the like generated in a dodging process can be prevented effectively.

Description

technical field [0001] The invention belongs to the field of femtosecond laser micro-nano processing optical devices, in particular to a method for preparing a quasi-periodic microlens array by wet etching with a femtosecond laser, which efficiently prepares a large-scale quasi-periodic microlens array on the surface of a hard material. The preparation result can be used as a uniform light device with high damage threshold. Background technique [0002] In many fields such as high-precision laser micro-nano processing and imaging, optical information processing, laser-driven inertial confinement nuclear fusion, and medical clinical applications of lasers, there are high requirements for the uniformity of the irradiation spot light intensity. Usually, the spatial intensity distribution of the laser beam generated by the laser is Gaussian. Therefore, obtaining a uniform spot through the Gaussian beam has always been a research hotspot at home and abroad. At present, diffracti...

AI Technical Summary

Problems solved by technology

At present, diffractive optical elements are commonly used. This kind of element has the characteristics of high diffraction efficiency and adjustable spot profile, but it has disadvantages such as complex design, difficult processing, and low laser damage threshold.

[0003] In the previous patent, it was proposed to use femtosecond laser wet etching method to fabricate rectangular or hexagonal uniformly arranged large-scale microlens arrays as a uniform light device, but the light source passes through uniformly arranged large-scale microlens arrays. After the lens array, there will be obvious periodic light field coupling superposition effect, which will affect the uniform light quality

Moreover, the production efficiency of uniformly arranged microlens arrays is limited, and it takes several or even dozens of hours to fabricate an array with an array size of centimeters.

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