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Proceedings Paper

Back-focal-plane interferometry: position or force detection?
Author(s): Arnau Farré; Estela Martín-Badosa; Mario Montes-Usategui
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Paper Abstract

We recently showed that force measurements through the detection of beam momentum changes can be implemented in single-beam gradient traps. We thereby achieved a method that renders force measurements insensitive to sample's geometrical and optical properties. Our instrument could be calibrated by a parameter that remained constant within a 4% error when, under comparable conditions, the traditional approach based on position detection could change by a factor of two or more. The setup required for these measurements was but a modified version of the apparatus used for position detection with back-focal-plane interferometry (BFPI). Despite the apparent difference between both techniques, we show here that they are not independent and we explicitly indicate the connection between them. The results suggest that our changes in the position detection instrument could have some important advantages and improve the technique when this is used to ultimately determine optical forces.

Paper Details

Date Published: 9 September 2011
PDF: 9 pages
Proc. SPIE 8097, Optical Trapping and Optical Micromanipulation VIII, 809705 (9 September 2011); doi: 10.1117/12.893307
Show Author Affiliations
Arnau Farré, Univ. de Barcelona (Spain)
Estela Martín-Badosa, Univ. de Barcelona (Spain)
Mario Montes-Usategui, Univ. de Barcelona (Spain)

Published in SPIE Proceedings Vol. 8097:
Optical Trapping and Optical Micromanipulation VIII
Kishan Dholakia; Gabriel C. Spalding, Editor(s)

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