Surface coloring by laser irradiation of solid substrates

Huagang Liu,Wenxiong Lin,Minghui Hong

doi:10.1063/1.5089778

Abstract

Laser marking has become a versatile method for industrial product identification because of its applicability to almost all kinds of solid materials in a simple and single-step process. However, traditional laser marking generally produces contrast marks which are often monochromatic. There is increasing interest in color marking by laser processing for decoration and visual attraction. This tutorial provides a digest of the recent advancement of laser coloring technologies for surface coloration. An overview of existing methods for laser coloring is summarized, and three distinct physics mechanisms behind color formation are discussed. It is found that the coloration of diverse solid surfaces originates from laser induced oxidation, surface structuring, and micro/nanoparticles generation. How the laser processing parameters and experimental conditions affect the resulting colors is also presented. The laser coloring technique is capable of producing complete Hue palettes on metal surfaces by the precise control of laser processing parameters and will find much more extensive applications.

Highlights

As a versatile and environment-friendly technology, laser marking is rapidly replacing traditional marking methods such as painting and printing.1 It has become a foremost industrial process today in many applications, such as the labeling of serial number, date, barcode, quick response (QR) code, company logo, trade marker, and other product information
Laser color marking is achieved by producing surface structures or oxidation films under the laser irradiation, which lead to the modification of optical properties in the visible range
According to the physics mechanisms, there are three main approaches to realize the surface colorizing: (1) laser induced oxidation and the thin film effect, or intrinsic colors of the oxides, (2) laser induced periodic surface structures (LIPSSs) and their diffraction, giving rise to iridescent colors, and (3) laser induced nanostructures and nanoparticles, which lead to high absorption at some wavelengths due to the Surface plasmon resonance (SPR) effect

Summary

INTRODUCTION

As a versatile and environment-friendly technology, laser marking is rapidly replacing traditional marking methods such as painting and printing. It has become a foremost industrial process today in many applications, such as the labeling of serial number, date, barcode, quick response (QR) code, company logo, trade marker, and other product information. Color marking by laser processing without using any chemicals has emerged as a novel and versatile technology to create various colors on solid substrate surfaces. Laser color marking is mainly achieved through three approaches: thin film interference effect of the surface oxide layer, laser induced periodic surface structures (LIPSSs), and plasmonic colors excited from metallic nanoparticles and nanostructures.. Surface plasmon resonance (SPR) effects arising from metallic nanostructures and nanoparticles are the main causes for this type of coloring. The scope of this tutorial is to present the recent advancement and the fundamental basics of laser color marking for surface coloration and decoration. Some important applications of the laser color marking are introduced

EXPERIMENTAL

LASER COLORING FROM SURFACE OXIDATION

ANGLE DEPENDENT COLORS ARISING FROM LIPSSs

DISCUSSION AND COMPARISON

SUMMARY