Femtosecond laser micro-explosion of plasma disk
发 光 学 论 坛
第2期
Femtosecond laser micro-explosion of plasma disk for nano-structuring inside thin transparent film
Prof. Peter R Herman
Department of Electrical and Computer Engineering, University of Toronto
时间: 2015年7月1日上午9:30
地点: 发光室5楼大会议室
摘要：In this talk, Femtosecond laser interactions are presented for highly resolved internal structuring inside transparent dielectric films. Strong nonlinear interactions are found to be confined over the bright Fabry-Perot interference fringes as formed by thin film interference, generating narrow nano-length scale plasma zones of 20 to 45 nm thickness. Micro-disk explosions are shown to cleave open the film into sub-wavelength internal cavities at single or multiple periodic depths at low laser exposure, while higher exposure will eject fractional film segments at various controllable depths. This spatially localized laser interaction follows the predicted l/2nfilm fringe spacing for 522, 800, and 1044 nm laser wavelengths. The process window is examined around the limiting effects of pulse duration in terms fringe blurring at ultrashort pulse duration through to thermal diffusion blurring at picosecond pulse duration.
This new form of high-resolution patterning is presented for SiNx and SiOx film, where Fresnel reflection supports sufficient fringe contrast to isolate the laser dissipation into nano-length scale zones. The process opens sub-wavelength internal cavities and forms thin membranes (~100 nm) at single or multiple film depths from which follows new directions of writing multilevel micro- or nano-fluidic channels inside dielectric film as well as ejecting nano-disks at quantized film depths. The process window on laser wavelength, pulse duration and coherence are presented together with time-resolved microscopic imaging of the quantized film ejections.
个人简介：
Peter R. Herman received the B.Eng. degree (1980) in Engineering Physics at McMaster University. He earned MASc (1982) and PhD (1986) degrees studying lasers and diatomic spectroscopy in the Physics Department at the University of Toronto that followed with a post-doctoral position at the Institute of Laser Engineering in Osaka University, Japan (1987) to the study of laser-plasma physics and x-ray lasers. He joined the Department of Electrical and Computer Engineering at the University of Toronto in 1988 where he holds a full professor position. Professor Herman directs a large and collaborative research group that develops and applies laser technology and advanced beam delivery systems to control and harvest laser interactions in new frontiers of 3-D nanofabrication. Professor Herman is OSA fellow, holds several patents, spun out one company (FiLaser), and has published over 300 papers in journals and conference proceedings.