Mid-infrared laser-induced superheating of water and its quantification by an optical temperature probe

Abstract

Free-running thulium laser pulses (Cr:Tm:YAG, lambda = 2.01 microm, tp = 300 micros) were applied to a purified, degassed water sample and the resulting temperature rise was investigated by an optical temperature probe. The probe detected water reflectance index changes with temperature and also the onset of vaporization, which was found to occur in a superheat regime, at approximately 230 degrees C. The experimental data were compared with theoretical temperature calculations, and deviations of less than 20 degrees C were stated. The best agreement between theory and experiment was found for temperatures below 180 degrees C, defining by this the method's high accuracy limit. In conclusion, both the optical temperature probe and the presented calculations can help to improve dosimetry in pulsed IR laser applications by precise temperature measurement and prediction.

Boiling nucleation on melanosomes and microbeads transiently heated by nanosecond and microsecond laser pulses

“…On silica surfaces a nucleation temperature of 250°C was found during pulsed laser heating. 36 These temperatures are similar to the nucleation temperatures we have measured for gold and magnetic silica beads.…”

IR laser assisted photothermal condensation in a microchannel

“…Hence, if the infrared laser is directly used to create the photothermal effect instead of using PNPs, the microsystems will become simple. To date, only a few studies on the direct use of infrared laser to heat up water and the phase change have been reported (Brendel and Brinkmann, 2004;Hobley et al, 2008;Xu et al, 2012;Liu et al, 2014). In this paper, therefore, the condensation behaviors in microchannels induced by the infrared laser with the wavelength of 1550 nm were visually investigated.…”

Untersuchungen zur IR-Laser-Ablation in Wasser

“…gelöst werden kann, wenn eine Darstellung des Verlaufs von µ § T ¨vorliegt. Die Temperaturänderungen von Dichte und spezifischer Wärme sind gegenüber denen der Absorption weitgehend vernachlässigbar [8].…”

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Charakteristisch für den freilaufenden Betrieb der Tm-und Ho-Lasersysteme ist ein ausgeprägtes Spiking während der Emission (Abbildung 2.2) [8,24].

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