Optical tweezers in a dusty universe

Abstract

Optical tweezers are powerful tools based on focused laser beams. They are able to trap, manipulate, and investigate a wide range of microscopic and nanoscopic particles in different media, such as liquids, air, and vacuum. Key applications of this contactless technique have been developed in many fields. Despite this progress, optical trapping applications to planetary exploration are still to be developed. Here we describe how optical tweezers can be used to trap and characterize extraterrestrial particulate matter. In particular, we exploit light scattering theory in the T-matrix formalism to calculate radiation pressure and optical trapping properties of a variety of complex particles of astrophysical interest. Our results open perspectives in the investigation of extraterrestrial particles on our planet, in controlled laboratory experiments, aiming for space tweezers applications: optical tweezers used to trap and characterize dust particles in space or on planetary bodies surface.

Investigation of Dust Grains by Optical Tweezers for Space Applications

“…In order to compare our experimental results with theoretical expectations, we calculate optical forces through the Maxwell stress tensor exploiting the multipole expansion and T-matrix formalism (Borghese et al 2007a;Polimeno et al 2018Polimeno et al , 2021. We consider particle models emulating the dust grains of the lunar meteorite DEW 12007.…”

“…We consider particle models emulating the dust grains of the lunar meteorite DEW 12007. Although all the trapped dust grains showed irregular shapes, for simplicity, we modeled our particles as microspheres having an average diameter d = 1 μm with a refractive index given by the Bruggeman mixing rule for the constituent minerals of DEW 12007, as shown in the inset of Figure 3(a) (Bohren & Huffman 2008;Polimeno et al 2021).…”

Investigation of dust grains by optical tweezers for space applications

“…In order to compare our experimental results with theoretical expectations, we calculate optical forces through the Maxwell stress tensor exploiting the multipole expansion and T-matrix formalism 29,39,40 . We consider particle models emulating the dust grains of the lunar meteorite DEW 12007.…”

“…We consider particle models emulating the dust grains of the lunar meteorite DEW 12007. Although all the trapped dust grains showed irregular shapes, for simplicity, we modelled our particles as micro-spheres having an average diameter d = 1 µm with a refractive index given by the Bruggeman mixing rule for the constituent minerals of DEW 12007, as showed in the inset of figure 3(a) 40,41 .…”

GEOLOGY WITHOUT BORDERS - 90° Congresso della Società Geologica Italiana

“…Coupled with Raman spectrometers, optical tweezers allow high-resolution (i.e., no background noise from substrate) spectroscopic analysis of physico-chemical properties of dust grains. Although in recent years they have been widely and successfully used in a variety of research fields (Jones et al,2015), their application in space science is in its infancy (Alali et al, 2020, Polimeno et al, 2021.…”