We have conducted experimental investigations for the micromachining of dielectrics (fused silica) using an in tegrated femtosecond (fs) and nanosecond (ns) dual-beam laser system at different time delays between the fs and ns pulses. We found that the maximum ablation enhancement occurs when the fs pulse is shot near the peak of the ns pulse envelope. Enhancements up to 13.4 times in ablation depth and 50.7 times in the amount of material removal were obtained, as compared to fs laser ablation alone. The fs pulse increases the free electron density and changes the optical properties of fused silica to have metallic characteristics, which increases the absorption of the ns laser energy. This study provides an opportunity for efficient micromachining of dielectrics.
© 2010 Optical Society of America
Lasers and Laser Optics
Original Manuscript: April 7, 2010
Revised Manuscript: June 19, 2010
Manuscript Accepted: June 25, 2010
Published: July 15, 2010
Cheng-Hsiang Lin, Zheng-Hua Rao, Lan Jiang, Wu-Jung Tsai, Ping-Han Wu, Chih-Wei Chien, Shean-Jen Chen, and Hai-Lung Tsai, "Investigations of femtosecond–nanosecond dual-beam laser ablation of dielectrics," Opt. Lett. 35, 2490-2492 (2010)