[18a-Z04-1~11] 3.7 Laser processing

△ [18a-Z04-10] Material Removal Threshold of Transient and Selective Laser Absorption into Excited Electrons in F used Silica

〇(D)Reina Yoshizaki¹, Sunya Yoshitake¹, Yusuke Ito¹, Wei Chaoran¹, Akihiro Shibata², Ikuo Nagasawa², Keisuke Nagato¹, Naohiko Sugita¹ (1.Univ. Tokyo, 2.AGC Inc.)

Keywords:ultrashort pulse laser, glass, electron excitation

Among the many glass microfabrication techniques, ultrashort pulse laser processing is superior in that it can be performed without contact and with a high presicion. However, this processing efficiency needs further development. We proposed a novel processing method, transient selective laser absorption(TSL) and succeeded in enhancing the drilling efficiency. In TSL, electrons in the glass are excited by an ultrashort pulse laser, and the electron-excited region absorbs a long pulse laser of low intensity and wavelength of which light are normally almost unabsorbable into glass. In this study, we measured the processing threshold of TSL on fused silica glass in order to investigate the details of the processing mechanism. From the experimental results, it was found that the processing threshold is represented by the relationship between the CW laser intensity and the ultrashort laser pulse electron excitation density.