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Moiré deflectometry-based position detection for optical tweezers

Khorshad, A. A ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1364/OL.42.003506
  3. Abstract:
  4. Optical tweezers have proven to be indispensable tools for pico-Newton range force spectroscopy. A quadrant photodiode (QPD) positioned at the back focal plane of an optical tweezers’ condenser is commonly used for locating the trapped object. In this Letter, for the first time, to the best of our knowledge, we introduce a moiré pattern-based detection method for optical tweezers. We show, both theoretically and experimentally, that this detection method could provide considerably better position sensitivity compared to the commonly used detection systems. For instance, position sensitivity for a trapped 2.17 μm polystyrene bead is shown to be 71% better than the commonly used QPD-based detection method. Our theoretical and experimental results are in good agreement. © 2017 Optical Society of America
  5. Keywords:
  6. Pattern recognition ; Back focal planes ; Detection methods ; Force spectroscopy ; Indispensable tools ; Polystyrene beads ; Position detection ; Position sensitivity ; Quadrant photodiodes ; Optical tweezers
  7. Source: Optics Letters ; Volume 42, Issue 17 , 2017 , Pages 3506-3509 ; 01469592 (ISSN)
  8. URL: https://www.osapublishing.org/ol/abstract.cfm?uri=ol-42-17-3506