Local laser heating

Writing Patterns into Polymer Films by Local Laser Heating. 162... 

Our simulations clearly demonstrate that without thermally driven mass diffusion the spatial variation of the control parameter b(T) due to the local laser heating does not provide the typical pattern evolution observed in the experiments. It is crucial to take the Soret effect in the basic equations into account in order to reproduce the phenomena observed in an experiment with local heating. 

Figure 5. Scattering intensity Ax for q = 0 as obtained from the OZ-plots as function of the reduced temperature. The original data ( ) are corrected for local laser heating and background scattering to give the scattering of the critical fluctuations (O)-...

Thermocapillary Flows and Interface Deformations Produced by Localized Laser Heating... 

Chraibi H, Delville JP (2012) Thermocapillary flows and interface deformations produced by localized laser heating in conflned environment. Phys Fluids 24 032102... 

Finally, it should be noted that contact angle hysteresis may be reduced by bathing the liquid drop in another liquid. Experiments have shown that a drop of water, immersed in oil, will show a very small amount of hysteresis and may be displaced through localized laser heating [7]. 

Method. The laser vaporization source eliminates the material constraints inherent in conventional oven sources. This is accomplished by localizing the heating to a very small area at the surface of the sample and by entraining the vapor produced in a rapid flow of high pressure gas. 

Figure 11. Schematic representation of a laser heating experiment in the DAC. The IR laser beam is directed onto the absorbing sample immersed in a compression medium acting also as thermal insulator. The thermal emission of the sample is employed for the temperature measurement, while the local pressure is obtained by the ruby fluorescence technique (see next section).

The use of an Intense laser light source with biological materials Is accompanied by the concomitant problems of localized sample heating and the possibility of protein denaturetlon. A further complication Introduced by resonance Raman spectroscopy Is the Increased potential for photochemical destruction of chromo-phorlc metal centers as a result of the absorption of large amounts of Incident radiation. Both of these situations may be ameliorated by freezing samples to liquid nitrogen temperature ( 90 K), while the even lower temperatures made possible with a closed-cycle... 

This assumption is indeed true for equilibrium scenarios with a homogeneous temperature distribution. Due to the coupling between heat and mass transport, laser heating gives rise to completely different behavior and can even drive a UCST-mixture locally from the homogeneous into the phase separated state. 

Karu TI. Local pulsed heating of absorbing chromophores as a possible primary mechanism of low-power laser effects. In Galetti G, Bolognani L, Ussia G (eds), Laser Applications in Medicine and Surgery. Bologna Monduzzi Editore, 1992. 

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