Gradient and nongradient contributions to plasmon-enhanced optical forces on silver nanoparticles

We use a computational method based on the discrete-dipole approximation (DDA) to calculate the gradient and nongradient contributions to optical forces on nanometer sized silver particles in water. We find that, due to a contribution that is usually neglected, nongradient forces are often non-negligible. This result is not a consequence of an approach to the dipole limit. We suggest that this method could provide useful input for a more detailed understanding of the physics relevant to optical trapping and binding phenomena.

[1]  Hongxing Xu,et al.  Surface-plasmon-enhanced optical forces in silver nanoaggregates. , 2002, Physical review letters.

[2]  Fuchs,et al.  Multipolar response of small metallic spheres: Nonlocal theory. , 1987, Physical review. B, Condensed matter.

[3]  M. Nieto-Vesperinas,et al.  Time-averaged total force on a dipolar sphere in an electromagnetic field. , 2000, Optics letters.

[4]  M. Nieto-Vesperinas,et al.  Near-field photonic forces , 2004, Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[5]  B. Draine,et al.  User Guide for the Discrete Dipole Approximation Code DDSCAT (Version 5a10) , 2000, astro-ph/0008151.

[6]  L. Novotný.  Forces in Optical Near-Fields , 2001 .

[7]  Bruce T. Draine,et al.  The discrete-dipole approximation and its application to interstellar graphite grains , 1988 .

[8]  Mikael Käll,et al.  Laser-induced growth of Ag nanoparticles from aqueous solutions. , 2002, Chemphyschem : a European journal of chemical physics and physical chemistry.

[9]  George C. Schatz,et al.  Plasmon resonance broadening in small metal particles , 1983 .

[10]  Mattias Goksör,et al.  Optical Spectroscopy of Single Trapped Metal Nanoparticles in Solution , 2004 .

[11]  Patrick C. Chaumet,et al.  Photonic force spectroscopy on metallic and absorbing nanoparticles , 2005 .

[12]  B. Draine,et al.  Discrete-dipole approximation with polarizabilities that account for both finite wavelength and target geometry. , 2003, Journal of the Optical Society of America. A, Optics, image science, and vision.

[13]  B. V. Bronk,et al.  Internal and scattered electric fields in the discrete dipole approximation , 1999 .

[14]  M. Nieto-Vesperinas,et al.  Modeling photonic force microscopy with metallic particles under plasmon eigenmode excitation , 2002 .

[15]  P. C. Chaumet,et al.  Optical binding of particles with or without the presence of a flat dielectric surface , 2001, physics/0305045.

[16]  Steven M. Block,et al.  Optical trapping of metallic Rayleigh particles. , 1994, Optics letters.

[17]  C. Mirkin,et al.  Controlling anisotropic nanoparticle growth through plasmon excitation , 2003, Nature.

[18]  Elinore M Mercer,et al.  Microfluidic sorting of mammalian cells by optical force switching , 2005, Nature Biotechnology.

[19]  Steven M. Block,et al.  Kinesin Moves by an Asymmetric Hand-OverHand Mechanism , 2003 .

[20]  Fredrik Svedberg,et al.  Laser-Induced Growth and Deposition of Noble-Metal Nanoparticles for Surface-Enhanced Raman Scattering , 2003 .

[21]  M. Chergui,et al.  Photochemically Grown Silver Nanoparticles with Wavelength-Controlled Size and Shape , 2003 .

[22]  J. Gordon,et al.  Stability of radiation-pressure particle traps: an optical Earnshaw theorem. , 1983, Optics letters.

[23]  Louis E. Brus,et al.  Silver Nanodisk Growth by Surface Plasmon Enhanced Photoreduction of Adsorbed [Ag+] , 2003 .

[24]  Lukas Novotny,et al.  Theory of Nanometric Optical Tweezers , 1997 .

[25]  A G Hoekstra,et al.  Radiation forces in the discrete-dipole approximation. , 2001, Journal of the Optical Society of America. A, Optics, image science, and vision.

[26]  P. C. Chaumet,et al.  Electromagnetic force on a metallic particle in the presence of a dielectric surface. , 2000 .

[27]  P. Chaumet,et al.  On the Importance of Local-Field Corrections for Polarizable Particles on a Finite Lattice: Application to the Discrete Dipole Approximation , 2004 .

[28]  L. Brus,et al.  Optical forces between metallic particles. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[29]  J. Gordon,et al.  Motion of atoms in a radiation trap , 1980 .

[30]  M. Nieto-Vesperinas,et al.  Optical forces on small particles: attractive and repulsive nature and plasmon-resonance conditions. , 2003, Journal of the Optical Society of America. A, Optics, image science, and vision.