Laser applications for subsurface characterization and modification
Abstract: Subsurface damage is a critical problem in ultraprecision machining of semiconductors and optics. It is extremely difficult to precisely measure the depth of the subsurface damage and remove them completely. In this talk, recent work by the speaker's group on subsurface characterization and modification by laser will be introduced. One topic is the quantitative characterization of subsurface damage depth in single-crystal silicon by laser micro-Raman spectroscopy, and the other is the complete recovery of the subsurface damage by laser annealing. The mechanisms and the realization conditions of the two methods will be highlighted, and some application examples will be given. Taking advantage of these laser techniques enables fast, non-contact and eco-friendly subsurface characterization and quality improvement for ultraprecision products.
Jiwang Yan obtained his Ph.D. from Tohoku University, Japan in 2000 and is currently a professor of Mechanical Engineering at Keio University, Japan (2012-), leading the Laboratory for Precision Machining and Nano Processing. His research areas include ultraprecision machining/metrology, micro/nano manufacturing, material processing and nanomechanics. As a principal investigator, he has led more than 20 nationally funded projects and over 70 joint research projects with industry. He has authored/co-authored 240+ peer-refereed journal papers, given 120+ keynote/invited talks, and received 30+ awards for his contribution in the manufacturing area. He serves on editorial boards of 10+ international journals including IJMTM, and is a member of JSME, JSPE, JSAP, JSAT, ASPE, euspen and CIRP, etc.
Personal homepage: http://www.yan.mech.keio.ac.jp/