Laser Ablation - From Picoseconds to Microseconds

Date: 
October 20, 2000 - 12:00pm
Location: 
Bldg. 90
Seminar Host/Point of Contact: 

Laser ablation is used in many applications, such as for the fabrication of new materials (nanomaterials, catalysts, superconductors), chemical analysis, medical surgery, semiconductor lithography, and many others. However, the fundamental mechanisms describing laser ablation are not established. Laser ablation involves processes that occur over several orders of magnitude in time. Understanding these processes is vital to optimizing this technology for these applications and for discovery of new applications. The basis of this research is to elucidate the fundamental mechanisms underlying laser ablation processes. This work investigates the laser induced plasma properties using picosecond time-resolved shadowgraphs, interferograms and spectroscopic measurements. Electron emission from target surface with an electron density on the order of 1020 cm-3 was the first process, which induces breakdown of air. The longitudinal expansion of this plasma was suppressed due to the development of a strong space-charge field. After electron emission, mass is removed from the target on the nanosecond scale. The electron number density and temperature of this mass plasma were deduced by measuring emission-line broadening. On the microsecond time scale, phase explosion occurs and large (> mm) particles are ejected. Time resolved shadowgraph images show that the rapid increase in crater depth at the threshold corresponds to large size droplets leaving the surface.

Add event to Google Calendar

Announcement List

To be added to our seminar annoucement list please, email ETA Seminars. Seminars may change without notice, stay informed by joining our seminar email list. 

Site Access

For site access please email your request to ETA Seminars. To arrive at Building 90 via the LBNL shuttle, take "Blue Uphill". Click here for the shuttle schedule. To ensure your site access is set-up send your request 36 hours in advance of the seminar.

Remote Access

Not able to attend in person? Remote participants can use ReadyTalk Audio & Net conference to phone in to listen, while viewing the presentation via the ReadyTalk site.

Web Access Code: 4864835

USA & Canada call-in number:
1 (866) 740-1260
Access Code: 4864835#

International callers:
Please visit this website to see if a toll-free call-in number is available for your international location.

If not, you will need to pay for the call yourself and use this phone number:

(303) 248-0285.