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

Gabriel C. Spalding; Patrick M. Dahl; Christine E.M. Démoré; Zhengi Yang; Peter Glynne-Jones; Andreas Melzer; Sandy Cochran; Michael P. MacDonald

doi:10.1117/12.2027136

26 September 2013 Mapping out tractor beams: topological angular momentum and reduced axial flux; gradient versus non-conservative forces

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

Author Affiliations +

Proceedings Volume 8810, Optical Trapping and Optical Micromanipulation X; 881004 (2013) https://doi.org/10.1117/12.2027136
Event: SPIE NanoScience + Engineering, 2013, San Diego, California, United States

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).

Citation Download Citation

Gabriel C. Spalding, Patrick M. Dahl, Christine E.M. Démoré, Zhengi Yang, Peter Glynne-Jones, Andreas Melzer, Sandy Cochran, and Michael P. MacDonald "Mapping out tractor beams: topological angular momentum and reduced axial flux; gradient versus non-conservative forces", Proc. SPIE 8810, Optical Trapping and Optical Micromanipulation X, 881004 (26 September 2013); https://doi.org/10.1117/12.2027136

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
15 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Acoustics

Actuators

Radiation effects

Physics

Scattering

Optical tweezers

Particles

Show All Keywords

Keywords/Phrases

Search In:

Publication Years