Scanning fast photothermal radiometry
Alejandro Mateos Canseco1, ⋆, Andrzej Kusiak1, Jean-Luc Battaglia1
⋆ : alejandro.mateos-canseco@u-bordeaux.fr
1 Institut de
Mécanique et d’Ingénierie, I2M
Mots clés : Photothermal radiometry;Thermal
conductivity;
Résumé :
The thermal characterization at micro or nano scale is of great
interest for numerous of technical and technological applications.
Assessment of heat transfer at microscale permits understanding behavior
and design of different kind of systems like microelectronic or
micro-electro-mechanical devices or effective properties of composite
materials.
In this context, at I2M laboratory, we use widely the photothermal
methods for thermal characterization of thin layer materials. One of
these methods is the modulated photothermal radiometry (MPTR) which is
well adapted to measure the out of plane thermal properties of thin
films. The modulated photothermal radiometry is a contactless
measurement technique based on monitoring the emitted infrared radiation
from the surface of the sample consequently to a periodic photothermal
excitation. The photothermal power from a modulated laser source is
absorbed by the surface of the sample leading to an increase in the
temperature at the heating area. This results in an increase in the
infrared emitted radiation and assuming small temperature increase the
emitted radiation can be linearized. On this way an indirect measurement
of the temperature at the sample surface is obtained. In this work, we
intend to develop a fast photothermal radiometry with several tenth of
microns in resolution in order to enable the in plane thermal
characterization. With the use an optical arrangement we manage the
formation of the heating and measurement spots at the sample surface.
The heating spot of 15 μm in
diameter is formed by focusing the laser; the measurement spot of 50
μm in dimeter is an image of
the detector over the sample surface. The sample mounted over a
translation stage permits it’s scanning with micrometric precision. The
use of modulated excitation allows exploring the frequencies up to 50
kHz. Under this configuration the in plane and out of plane heat
conduction is possible to be assessed.
doi : https://doi.org/10.25855/SFT2022-072
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