White marking inside the transparent plastic materials by 1.55 µm nanosecond pulse fiber laser

Abstract

In this paper, we report it is possible to create a white marking inside transparent plastic materials by heating them to the temperature close to the threshold of creating a void and using a fiber laser. Heating plastic materials and using a fiber laser enables the threshold to be excessed only in the focus position, and a white marking is created. We experimented with polycarbonate and polyethylene terephthalate as the transparent plastic materials, and a 1.55 µm nanosecond pulse fiber laser as the laser equipment. We irradiated laser in the sample inside while heating. As a result, when polycarbonate was heated to 150°C and polyethylene terephthalate to 50°C, a void was created at the focus position. Therefore, we successfully created a white marking inside the transparent plastic materials by heating them and using a fiber laser.