Mapping out tractor beams: Topological angular momentum and reduced axial flux; gradient versus non-conservative forces

Gabriel C. Spalding (Lead / Corresponding author), Patrick M. Dahl, Christine E. Démoré, Zhengi Yang, Peter Glynne-Jones, Andreas Melzer, Sandy Cochran, Michael P. MacDonald

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    We experimentally demonstrate continuous attraction of macroscopic targets (> 1 cm) towards the source, against a net momentum flux in the system. Use of a simple setup provides an easily understood illustration of the negative radiation pressure concept for tractor beam, and how these are distinct from the gradient force acting in conventional optical tweezers. Here, we map out regimes over which negative radiation forces dominate, and (favorably) compare the thresholds observed to those that emerge from simulations. Theoretical explorations of tractor beam action commonly invoke higher-order Bessel beams, and here we make clear that the reason for this is because of the reduction in axial momentum associated with such hollow-core beams, which allows effects associated with off-axis “skew” momentum to become dominant. Ultimately, there is interest in exploring the language used for describing such effects: radiation pressure versus gradient force (which we suggest might be better described in terms of non-conservative versus conservative forces), and “orbital” angular momentum (which we suggest might be more appropriately termed “topological” angular momentum).
    Original languageEnglish
    Title of host publicationOptical Trapping and Optical Micromanipulation X
    EditorsKishan Dholakia, Gabriel C. Spalding
    Place of PublicationBellingham
    PublisherSPIE-International Society for Optical Engineering
    ISBN (Print)9780819496607
    DOIs
    Publication statusPublished - 2013
    EventSPIE Optics+Photonics 2013: Optical Trapping and Optical Micromanipulation X - San Diego Convention Center, San Diego, United States
    Duration: 25 Aug 201329 Aug 2013
    http://spie.org/x103812.xml

    Publication series

    NameProceedings of SPIE
    PublisherSPIE
    Volume8810

    Conference

    ConferenceSPIE Optics+Photonics 2013: Optical Trapping and Optical Micromanipulation X
    CountryUnited States
    CitySan Diego
    Period25/08/1329/08/13
    Internet address

    Fingerprint

    nonconservative forces
    tractors
    angular momentum
    gradients
    radiation pressure
    momentum
    pressure gradients
    attraction
    hollow
    orbitals
    thresholds
    radiation
    simulation

    Cite this

    Spalding, G. C., Dahl, P. M., Démoré, C. E., Yang, Z., Glynne-Jones, P., Melzer, A., ... MacDonald, M. P. (2013). Mapping out tractor beams: Topological angular momentum and reduced axial flux; gradient versus non-conservative forces. In K. Dholakia, & G. C. Spalding (Eds.), Optical Trapping and Optical Micromanipulation X [881004] (Proceedings of SPIE; Vol. 8810). Bellingham: SPIE-International Society for Optical Engineering. https://doi.org/10.1117/12.2027136
    Spalding, Gabriel C. ; Dahl, Patrick M. ; Démoré, Christine E. ; Yang, Zhengi ; Glynne-Jones, Peter ; Melzer, Andreas ; Cochran, Sandy ; MacDonald, Michael P. / Mapping out tractor beams : Topological angular momentum and reduced axial flux; gradient versus non-conservative forces. Optical Trapping and Optical Micromanipulation X. editor / Kishan Dholakia ; Gabriel C. Spalding. Bellingham : SPIE-International Society for Optical Engineering, 2013. (Proceedings of SPIE).
    @inproceedings{017da3420a21447595ab2fcb182fed2b,
    title = "Mapping out tractor beams: Topological angular momentum and reduced axial flux; gradient versus non-conservative forces",
    abstract = "We experimentally demonstrate continuous attraction of macroscopic targets (> 1 cm) towards the source, against a net momentum flux in the system. Use of a simple setup provides an easily understood illustration of the negative radiation pressure concept for tractor beam, and how these are distinct from the gradient force acting in conventional optical tweezers. Here, we map out regimes over which negative radiation forces dominate, and (favorably) compare the thresholds observed to those that emerge from simulations. Theoretical explorations of tractor beam action commonly invoke higher-order Bessel beams, and here we make clear that the reason for this is because of the reduction in axial momentum associated with such hollow-core beams, which allows effects associated with off-axis “skew” momentum to become dominant. Ultimately, there is interest in exploring the language used for describing such effects: radiation pressure versus gradient force (which we suggest might be better described in terms of non-conservative versus conservative forces), and “orbital” angular momentum (which we suggest might be more appropriately termed “topological” angular momentum).",
    author = "Spalding, {Gabriel C.} and Dahl, {Patrick M.} and D{\'e}mor{\'e}, {Christine E.} and Zhengi Yang and Peter Glynne-Jones and Andreas Melzer and Sandy Cochran and MacDonald, {Michael P.}",
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    language = "English",
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    Spalding, GC, Dahl, PM, Démoré, CE, Yang, Z, Glynne-Jones, P, Melzer, A, Cochran, S & MacDonald, MP 2013, Mapping out tractor beams: Topological angular momentum and reduced axial flux; gradient versus non-conservative forces. in K Dholakia & GC Spalding (eds), Optical Trapping and Optical Micromanipulation X., 881004, Proceedings of SPIE, vol. 8810, SPIE-International Society for Optical Engineering, Bellingham, SPIE Optics+Photonics 2013: Optical Trapping and Optical Micromanipulation X, San Diego, United States, 25/08/13. https://doi.org/10.1117/12.2027136

    Mapping out tractor beams : Topological angular momentum and reduced axial flux; gradient versus non-conservative forces. / Spalding, Gabriel C. (Lead / Corresponding author); Dahl, Patrick M.; Démoré, Christine E.; Yang, Zhengi; Glynne-Jones, Peter; Melzer, Andreas; Cochran, Sandy; MacDonald, Michael P.

    Optical Trapping and Optical Micromanipulation X. ed. / Kishan Dholakia; Gabriel C. Spalding. Bellingham : SPIE-International Society for Optical Engineering, 2013. 881004 (Proceedings of SPIE; Vol. 8810).

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

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    AU - Dahl, Patrick M.

    AU - Démoré, Christine E.

    AU - Yang, Zhengi

    AU - Glynne-Jones, Peter

    AU - Melzer, Andreas

    AU - Cochran, Sandy

    AU - MacDonald, Michael P.

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    N2 - We experimentally demonstrate continuous attraction of macroscopic targets (> 1 cm) towards the source, against a net momentum flux in the system. Use of a simple setup provides an easily understood illustration of the negative radiation pressure concept for tractor beam, and how these are distinct from the gradient force acting in conventional optical tweezers. Here, we map out regimes over which negative radiation forces dominate, and (favorably) compare the thresholds observed to those that emerge from simulations. Theoretical explorations of tractor beam action commonly invoke higher-order Bessel beams, and here we make clear that the reason for this is because of the reduction in axial momentum associated with such hollow-core beams, which allows effects associated with off-axis “skew” momentum to become dominant. Ultimately, there is interest in exploring the language used for describing such effects: radiation pressure versus gradient force (which we suggest might be better described in terms of non-conservative versus conservative forces), and “orbital” angular momentum (which we suggest might be more appropriately termed “topological” angular momentum).

    AB - We experimentally demonstrate continuous attraction of macroscopic targets (> 1 cm) towards the source, against a net momentum flux in the system. Use of a simple setup provides an easily understood illustration of the negative radiation pressure concept for tractor beam, and how these are distinct from the gradient force acting in conventional optical tweezers. Here, we map out regimes over which negative radiation forces dominate, and (favorably) compare the thresholds observed to those that emerge from simulations. Theoretical explorations of tractor beam action commonly invoke higher-order Bessel beams, and here we make clear that the reason for this is because of the reduction in axial momentum associated with such hollow-core beams, which allows effects associated with off-axis “skew” momentum to become dominant. Ultimately, there is interest in exploring the language used for describing such effects: radiation pressure versus gradient force (which we suggest might be better described in terms of non-conservative versus conservative forces), and “orbital” angular momentum (which we suggest might be more appropriately termed “topological” angular momentum).

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    Spalding GC, Dahl PM, Démoré CE, Yang Z, Glynne-Jones P, Melzer A et al. Mapping out tractor beams: Topological angular momentum and reduced axial flux; gradient versus non-conservative forces. In Dholakia K, Spalding GC, editors, Optical Trapping and Optical Micromanipulation X. Bellingham: SPIE-International Society for Optical Engineering. 2013. 881004. (Proceedings of SPIE). https://doi.org/10.1117/12.2027136