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Göteborgs universitets publikationer

Measurement of particle motion in optical tweezers embedded in a Sagnac interferometer

Författare och institution:
Ivan Galinskiy (Institutionen för fysik (GU)); Oscar Isaksson (Institutionen för fysik (GU) & Institutionen för teknisk fysik, Chalmers); Israel Rebolledo Salgado (Institutionen för fysik (GU)); Mathieu Hautefeuille (-); Bernhard Mehlig (Institutionen för fysik (GU)); Dag Hanstorp (Institutionen för fysik (GU))
Publicerad i:
Optics Express, 23 s. 27071-27084
Artikel, refereegranskad vetenskaplig
Sammanfattning (abstract):
We have constructed a counterpropagating optical tweezers setup embedded in a Sagnac interferometer in order to increase the sensitivity of position tracking for particles in the geometrical optics regime. Enhanced position determination using a Sagnac interferometer has previously been described theoretically by Taylor et al. [Journal of Optics 13, 044014 (2011)] for Rayleigh-regime particles trapped in an antinode of a standing wave. We have extended their theory to a case of arbitrarily-sized particles trapped with orthogonally-polarized counter-propagating beams. The working distance of the setup was sufficiently long to optically induce particle oscillations orthogonally to the axis of the tweezers with an auxiliary laser beam. Using these oscillations as a reference, we have experimentally shown that Sagnac-enhanced back focal plane interferometry is capable of providing an improvement of more than 5 times in the signal-to-background ratio, corresponding to a more than 30-fold improvement of the signal-to-noise ratio. The experimental results obtained are consistent with our theoretical predictions. In the experimental setup, we used a method of optical levitator-assisted liquid droplet delivery in air based on commercial inkjet technology, with a novel method to precisely control the size of droplets.
Ämne (baseras på Högskoleverkets indelning av forskningsämnen):
Postens nummer:
Posten skapad:
2015-11-30 08:26
Posten ändrad:
2016-03-20 13:17

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