Ultrafast laser-based metrology for micron-scale measurements of thermal transport, coefficient of thermal expansion, and temperature
Event details
| Date | 16.09.2011 |
| Hour | 10:00 |
| Speaker | Prof. David Cahill, University of Illinois |
| Location | |
| Category | Conferences - Seminars |
Pump-probe measurements using ultrafast lasers are a standard metrology tool for determining film thickness e.g. the Rudolph MetaPULSE. Over the past several years we have developed pump-probe techniques for measuring the thermophysical properties of materials with high spatial resolution accuracy and sensitivity. Measurements of the thermal conductivity of thin films and spatially resolved mapping of the thermal conductivity of bulk specimens is now routine: while in the past a measurement of a thin layer was a significant research endeavor we can now perform these measurements with a level of effort that is comparable to ellipsometry of optical constants. Recently we have extended the capabilities of pump-probe optical metrology to include quantitative measurements of the coefficient of thermal expansion. The spatial resolution is controlled by the laser spot size (typically a few microns) and the thermal penetration depth of the thermal waves (typically a few hundred nanometers). Pump-probe measurements of two-photon absorption within Si provides a surprisingly sensitive thermometer with a spatial resolution below 10 μm3.
Practical information
- General public
- Free
Contact
- Ludger Weber