# Surface quasi periodic and random structures based on nanomotor lithography for light trapping

## TL;DR

This paper compares Gaussian random and quasi-random azopolymer surface patterns created by laser illumination, demonstrating that quasi-random gratings enhance light trapping efficiency by up to 40%, useful for optical applications.

## Contribution

It introduces a simple laser-based method to produce quasi-random and random surface structures with improved light trapping capabilities.

## Key findings

- Quasi-random gratings improve light trapping efficiency by 20-40%.
- Surface patterns can be replicated on elastomeric materials.
- Laser illumination creates controllable surface structures.

## Abstract

We compare the characteristics of two types of patterns obtained with two azopolymer materials: a Gaussian random pattern and a quasi-random grating pattern. The surface structurations have been obtained with a simple bottom-up technique by illuminating azopolymer thin films with a single laser beam. We demonstrate the interesting generated properties of these two surfaces. In particular, the surface with quasi-random gratings can address beam splittings for light coupling in different directions in an ultra-thin film. We use these two surfaces as a mold and replicate them on a transparent elastomeric material and we demonstrate a very good light entrapment. We also show that the efficiency of light trapping is 20% better with the quasi-random gratings than with the Gaussian random surface, and is close to 40%.

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Source: https://tomesphere.com/paper/1706.06633