Probing the Casimir force with optical tweezers

We propose to use optical tweezers to probe the Casimir interaction between microspheres inside a liquid medium for geometric aspect ratios far beyond the validity of the widely employed proximity force approximation. This setup has the potential for revealing unprecedented features associated to th...

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Bibliographic Details
Published in:Europhysics letters 2015-11, Vol.112 (4), p.44001-p1-44001-p7
Main Authors: Ether, D. S., Pires, L. B., Umrath, S., Martinez, D., Ayala, Y., Pontes, B., de S. Araújo, G. R., Frases, S., Ingold, G.-L., Rosa, F. S. S., Viana, N. B., Nussenzveig, H. M., Maia Neto, P. A.
Format: Article
Language:English
Subjects:
42.50.Ct
82.70.Dd
87.80.Cc
Approximation
Aspect ratio
Attraction
Liquids
Mathematical analysis
Microspheres
Molecular biology
Paving
Polystyrene resins
Quantum optics
Saline solutions
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Summary:We propose to use optical tweezers to probe the Casimir interaction between microspheres inside a liquid medium for geometric aspect ratios far beyond the validity of the widely employed proximity force approximation. This setup has the potential for revealing unprecedented features associated to the non-trivial role of the spherical curvatures. For a proof of concept, we measure femtonewton double-layer forces between polystyrene microspheres at distances above 400 nm by employing very soft optical tweezers, with stiffness of the order of fractions of a fN/nm. As a future application, we propose to tune the Casimir interaction between a metallic and a polystyrene microsphere in saline solution from attraction to repulsion by varying the salt concentration. With those materials, the screened Casimir interaction may have a larger magnitude than the unscreened one. This line of investigation has the potential for bringing together different fields including classical and quantum optics, statistical physics and colloid science, while paving the way for novel quantitative applications of optical tweezers in cell and molecular biology.
ISSN:0295-5075
1286-4854
DOI:10.1209/0295-5075/112/44001