Optical Tweezers And Optical Spanners With Laguerre-Gaussian Modes

Simpson, N., Allen, L. and Padgett, M. (1996) Optical Tweezers And Optical Spanners With Laguerre-Gaussian Modes. Journal of Modern Optics, 43(12), pp. 2485-2491.

Abstract

We numerically model the axial trapping forces within optical tweezers arising from Laguerre-Gaussian laser modes. For an 8 mu m diameter sphere suspended in water, the higher-order modes produce an axial trapping force several times larger than that of the fundamental. Partial absorption results in a transfer of the orbital angular momentum from the Laguerre-Gaussian mode to the trapped particle. This results in the rotation of the particle by what may be called an optical spanner (wrench). For an absorption coefficient of alpha = 5700 m(-1) and a laser power of 10 mW, we find that an 8 mu m diameter sphere would acquire an angular acceleration of 10 x 10(4) rad s(-2) and a limiting angular velocity of 0.2 rad s(-1).

• Item Type: Articles
• Keywords: Wollaston prism; multichannel Fourier-transform spectroscopy; field of view; optical throughput; etendue
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Padgett, Professor Miles
• Authors: Simpson, N., Allen, L., and Padgett, M.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Journal of Modern Optics
• Journal Abbr.: J. Mod. Opt.
• ISSN: 0950-0340