Ultrashort pulse laser processing has been proved as an efficient method of microfabricating dielectric materials such as silicon carbide, sapphire, and glass, yet damages are formed around the processed area. In this study, we combine a pump-probe imaging system with a high-speed camera to visualize the ultrafast phenomena of each pulse irradiation and identify the mechanism of damage generation of dielectric materials. In addition, the observations are conducted with various pulse widths to clarify the dependence on the processing conditions. The results demonstrate that the damage is mainly caused by the electron excitation and stress wave propagation.
Many materials with wide bandgap, such as glasses, sapphire, and silicon carbide (SiC), have excellent optical, electrical, and mechanical properties and are used in various industrial and scientific applications. Ultrashort pulse laser processing has been attracting attention as a method of micromachining wide-bandgap materials. Because the peak intensity of ultrashort pulse laser is extremely high, its focused pulse can make wide-bandgap materials absorb its light energy via multiphoton absorption. However, it has a problem that damage occurs around the processed region. In this study, we observe the high-speed phenomena during the ultrashort pulse laser drilling of wide-bandgap materials using pump-probe imaging in combination with a high-speed camera to clarify the mechanism of damage generation. This method visualizes both the static phenomena such as the processed shape and the damage, and the dynamic phenomena such as the electron excitation and the stress wave propagation, which change with each pulse irradiation. In addition, we conduct the experiments by changing the pulse width and the material to be processed to investigate the dependence of damage generation on the processing condition. The results show that stress waves propagating inside the material during processing cause the damage, and that the damage generation pattern changes depending on the pulse width and material. This study contributes to optimizing the processing conditions to suppress the damage during the ultrashort pulse laser processing of wide-bandgap materials.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.