Laser Techniques on Acoustically Levitated Droplets

¹ Department of Mathematical and Informatics Sciences, Physical Sciences and Earth Sciences, Messina University, Viale F. Stagno D’Alcontres 31, 98166 Messina, Italy
² Italian Air Force Meteorological Service, Comando Aeroporto, Sigonella, Catania, Italy

^* Corresponding author: acannuli@unime.it

Published online: 9 January 2018

Abstract

This work reports the results of an experimental study where laser techniques are applied to acoustically levitated droplets of trehalose aqueous solutions in order to perform spectroscopic analyses as a function of concentration and to test the theoretical diameter law. The study of such systems is important in order to better understand the behaviour of trehalose-synthesizing extremophiles that live in extreme environments. In particular, it will be shown how acoustic levitation, combined with optical spectroscopic instruments allows to explore a wide concentration range and to test the validity of the diameter law as a function of levitation lag time, i.e. the D² vs t law. On this purpose a direct diameter monitoring by a video camera and a laser pointer was first performed; then the diameter was also evaluated by an indirect measure through an OH/CH band area ratio analysis of collected Raman and Infrared spectra. It clearly emerges that D² vs t follows a linear trend for about 20 minutes, reaching then a plateau at longer time. This result shows how trehalose is able to avoid total water evaporation, this property being essential for the surviving of organisms under extreme environmental conditions.