Observation and simulation of an optically driven micromotor

In the realm of low Reynolds number flow there is a need to find methods to pump, move and mix minute amounts of analyte. Interestingly, micro-devices performing such actuation can be initiated by means of the light–matter interaction. Light induced forces and torques are exerted on such micro-objects, which are then driven by the optical gradient or scattering force. Here, different driving geometries can be realized to harness the light induced force. For example, the scattering force enables micro-gears to be operated in a tangential setup where the micromotor rotors are in line with an optical waveguide. The operational geometry we investigate has the advantage that it reduces the complexity of the driving of such a device in a microfluidic environment by delivering the actuating light by means of a waveguide or fiber optic. In this paper we explore the case of a micromotor being driven by a fiber optically delivered light beam. We experimentally investigate how the driving light interacts with and diffracts from the motor, utilizing two-photon imaging. The micromotor rotation rate dependence on the light field parameters is explored. Additionally, a theoretical model based on the paraxial approximation is used to simulate the torque and predict the rotation rate of such a device and compare it with experiment. The results presented show that our model can be used to optimize the micromotor performance and some example motor designs are evaluated.

[1]  Kishan Dholakia,et al.  Optical manipulation of nanoparticles: a review , 2008 .

[2]  Koji Ikuta,et al.  Force-controllable, optically driven micromachines fabricated by single-step two-photon microstereolithography , 2003 .

[3]  Ruxin Li,et al.  Nonlinear propagation of fs laser pulses in liquids and evolution of supercontinuum generation. , 2005, Optics express.

[4]  Iver Brevik,et al.  Experiments in phenomenological electrodynamics and the electromagnetic energy-momentum tensor , 1979 .

[5]  Norman R. Heckenberg,et al.  Optical torque and symmetry , 2004, SPIE Optics + Photonics.

[6]  R. Gauthier.  Ray optics model and numerical computations for the radiation pressure micromotor , 1995 .

[7]  Timo A. Nieminen.  Comment on "Geometric absorption of electromagnetic angular momentum", C. Konz, G. Benford , 2004 .

[8]  Shoji Maruo,et al.  Optically driven viscous micropump using a rotating microdisk , 2007 .

[9]  R. Gauthier,et al.  Activation of microcomponents with light for micro-electro-mechanical systems and micro-optical-electro-mechanical systems applications. , 2002, Applied optics.

[10]  M. Ashman,et al.  Simulated dynamic behavior of single and multiple spheres in the trap region of focused laser beams. , 1998, Applied optics.

[11]  S. Neale,et al.  All-optical control of microfluidic components using form birefringence , 2005, Nature materials.

[12]  Dong Xiao,et al.  Flow imaging by use of femtosecond-laser-induced two-photon fluorescence. , 2004, Optics letters.

[13]  S. Chu,et al.  Observation of a single-beam gradient force optical trap for dielectric particles. , 1986, Optics letters.

[14]  W Sibbett,et al.  Visualization of optical binding of microparticles using a femtosecond fiber optical trap. , 2006, Optics express.

[15]  Pál Ormos,et al.  Complex micromachines produced and driven by light , 2001, CLEO 2002.

[16]  P. Chaumet,et al.  Coupled dipole method to compute optical torque: Application to a micropropeller , 2007 .

[17]  Kishan Dholakia,et al.  Imaging in optical micromanipulation using two-photon excitation , 2004 .

[18]  T. Krauss,et al.  Integrated monolithic optical manipulation. , 2006, Lab on a chip.

[19]  A Mitchell,et al.  Application of optical trapping to beam manipulation in optofluidics. , 2005, Optics express.

[20]  Halina Rubinsztein-Dunlop,et al.  Optically driven micromachine elements , 2001 .

[21]  P. Ormos,et al.  Integrated optical motor. , 2006, Applied optics.

[22]  P. Waterman,et al.  SYMMETRY, UNITARITY, AND GEOMETRY IN ELECTROMAGNETIC SCATTERING. , 1971 .

[23]  H. Rubinsztein-Dunlop,et al.  Symmetry and the generation and measurement of optical torque , 2008, 0812.2039.

[24]  Norman R. Heckenberg,et al.  Optical angular momentum transfer to microrotors fabricated by two-photon photopolymerization , 2009 .

[25]  Hiroo Ukita,et al.  Optical rotor capable of controlling clockwise and counterclockwise rotation in optical tweezers by displacing the trapping position. , 2010, Applied optics.

[26]  N. K. Metzger,et al.  Observation of bistability and hysteresis in optical binding of two dielectric spheres. , 2006, Physical review letters.

[27]  Masud Mansuripur,et al.  Radiation pressure and the distribution of electromagnetic force in dielectric media. , 2005 .

[28]  Alex Terray,et al.  Microfluidic Control Using Colloidal Devices , 2002, Science.

[29]  K Dholakia,et al.  Optically bound microscopic particles in one dimension. , 2004, Physical review. E, Statistical, nonlinear, and soft matter physics.