Thu, 21 Aug 2008 06:50:54 BST CiteULike: rodney's radiation http://www.citeulike.org/user/rodney/tag/radiation CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/rodney/article/2953395 <i>Physical Review B (Condensed Matter and Materials Physics), Vol. 77, No. 24. (2008)</i><br /><br />We establish a theoretical framework that provides a bridge between the microscopic to macroscopic descriptions of the radiation force (RF) under a quantum resonance condition. By using this framework, we derive an explicit analytical expression to clearly demonstrate the properties of the resonant RF on nanostructures and related novel phenomena. (i) For a single nano-object the RF drastically changes with the size, shape, and quality of a nano-object due to the spatial correlations of the internal radiation field and the matter-excited states. This property is highly advantageous in the selective manipulation of quantum properties of nano-objects. (ii) For multiple nano-objects an attractive (repulsive) interobject radiation force (IRF) arises between nano-objects under the optical excitation of a particular coupled state of their spatially separated polaritons, and we term this state as “polaritonic molecule.” This IRF can be enhanced even between the nano-objects that have a large spatial separation if there exist intermediate nano-objects even with very weak induced polarizations, and this effect is termed as “superinterobject radiation force.” In addition, we clarify that a “negative dissipative force” arises when the electronic polarization in a particular nano-object is inverted by a photomediated interaction. Since the resonant RF and IRF depend on many degrees of freedom of both nanostructures and light, they will provide a great variety of optical control methods for the collective dynamics of nanocomposite materials. Theory of resonant radiation force exerted on nanostructures by optical excitation of their quantum states: From microscopic to macroscopic descriptions Takuya Iida Hajime Ishihara doi:10.1103/PhysRevB.77.245319 Physical Review B (Condensed Matter and Materials Physics), Vol. 77, No. 24. (2008) 2008-07-02T20:15:29-00:00 2008 Physical Review B (Condensed Matter and Materials Physics) 77 24 APS citedby nanoparticles optical pressure quantum radiation resonance thoery trap tweezers http://www.citeulike.org/user/rodney/article/2364317 <i>Astrophys. J., Vol. 333 (October 1988), pp. 848-872.</i><br /><br />The discrete dipole approximation (DDA), a flexible method for computing scattering of radiation by particles of arbitrary shape, is extended to incorporate the effects of radiative reaction and to allow for possible anisotropy of the dielectric tensor of the material. Formulas are given for the evaluation of extinction, absorption, scattering, and polarization cross sections. A simple numerical algorithm based on the method of conjugate gradients is found to provide an efficient and robust method for obtaining accurate solutions to the scattering problem. The method works well for absorptive, as well as dielectric, grain materials. Two validity criteria for the DDA are presented. The DDA is then used to compute extinction cross sections for spherical graphite grains and to calculate extinction cross sections for nonspherical graphite grains with three different geometries. It is concluded that the interstellar 2175 A extinction feature could be produced by small graphite grains which should have aspect ratios not far from unity. The discrete-dipole approximation and its application to interstellar graphite grains BT Draine doi:10.1086/166795 Astrophys. J., Vol. 333 (October 1988), pp. 848-872. 2008-02-12T01:04:37-00:00 1988 Astrophys. J. 333 848 872 ao_2002 dda dipole forces interstellar optical pressure radiation tweezers http://www.citeulike.org/user/rodney/article/2364311 <i>Opt. Lett., Vol. 8, No. 10. (1 October 1983), 511.</i> Stability of radiation-pressure particle traps: an optical Earnshaw theorem A Ashkin JP Gordon Opt. Lett., Vol. 8, No. 10. (1 October 1983), 511. 2008-02-12T00:59:26-00:00 1983 Opt. Lett. 8 10 511 OSA ao_2002 earnshaw optical pressure radiation stability trap tweezers http://www.citeulike.org/user/rodney/article/2338129 <i>J. Opt. Soc. Am. A, Vol. 18, No. 8. (2001), pp. 1944-1953.</i><br /><br />The theory of the discrete-dipole approximation (DDA) for light scattering is extended to allow for the calculation of radiation forces on each dipole in the DDA model. Starting with the theory of Draine and Weingartner [Astrophys. J. 470 , 551 (1996)] we derive an expression for the radiation force on each dipole. These expressions are reformulated into discrete convolutions, allowing for an efficient, O(N log N) evaluation of the forces. The total radiation pressure on the particle is obtained by summation of the individual forces. The theory is tested on spherical particles. The resulting accumulated radiation forces are compared with Mie theory. The accuracy is within the order of a few percent, i.e., comparable with that obtained for extinction cross sections calculated with the DDA. Radiation forces in the discrete-dipole approximation AG Hoekstra M Frijlink LBFM Waters PMA Sloot J. Opt. Soc. Am. A, Vol. 18, No. 8. (2001), pp. 1944-1953. 2008-02-06T01:26:30-00:00 2001 J. Opt. Soc. Am. A 18 8 1944 1953 OSA dda dipole discrete forces optical radiation theory tweezers http://www.citeulike.org/user/rodney/article/2338099 <i>Physical Review Letters, Vol. 83, No. 22. (29 November 1999), 4534.</i><br /><br />We report the first numerical analysis of the radiation force exerted on a subwavelength particle by an evanescent field localized near a subwavelength aperture. The radiation force is calculated by using the Maxwell stress tensor through the electric field distribution obtained with the finite-difference time-domain method. The result indicates that a particle moves towards the aperture. We found that if two particles exist the first particle is trapped and the second one is also attracted to the first one. The radiation force is found to be larger than the forces due to thermal fluctuations and to gravity. Radiation Force Exerted on Subwavelength Particles near a Nanoaperture K Okamoto S Kawata doi:10.1103/PhysRevLett.83.4534 Physical Review Letters, Vol. 83, No. 22. (29 November 1999), 4534. 2008-02-06T01:14:58-00:00 1999 Physical Review Letters 83 22 4534 American Physical Society forces nanoaperture optical particle radiation tweezers http://www.citeulike.org/user/rodney/article/2338073 <i>Applied Physics Letters, Vol. 71, No. 1. (1997), pp. 37-39.</i><br /><br />  Three-dimensional potential analysis of radiation pressure exerted on a single microparticle Keiji Sasaki Mitsuru Tsukima Hiroshi Masuhara Applied Physics Letters, Vol. 71, No. 1. (1997), pp. 37-39. 2008-02-06T01:07:35-00:00 1997 Applied Physics Letters 71 1 37 39 AIP 3-d boltzmann optical pressure radiation theory tweezers http://www.citeulike.org/user/rodney/article/2338067 <i>Optics Communications, Vol. 124, No. 5-6. (15 March 1996), pp. 529-541.</i><br /><br />Theoretical expressions of the radiation pressure force for a dielectric sphere in the Rayleigh regime of light scattering under illumination of a Gaussian laser beam with the fundamental mode are derived in explicit form as a function of measurable quantities of the beam parameter in MKS units. Correctness of the derived expressions and validity of the size range of the Rayleigh approximation for the radiation forces as a sum of the scattering force and the gradient force are investigated by a graphical comparison of the calculated forces in longitudinal and transverse components with those obtained from the generalized Lorenz-Mie theory. Fairly good agreement in both components is found within ordinary particle-size ranges of the Rayleigh scattering theory. Furthermore, the good agreement in the transverse component, where the gradient force is dominant, is found to be satisfactory beyond the existing criterion in particle size of the Rayleigh scattering theory until the particle size becomes comparable with the spot size of the illuminating laser beam. Radiation forces on a dielectric sphere in the Rayleigh scattering regime Yasuhiro Harada Toshimitsu Asakura doi:10.1016/0030-4018(95)00753-9 Optics Communications, Vol. 124, No. 5-6. (15 March 1996), pp. 529-541. 2008-02-06T01:05:06-00:00 1996 Optics Communications 124 5-6 529 541 ao_2002 dielectric forces optical radiation rayleigh scattering sphere theory tweezers http://www.citeulike.org/user/rodney/article/2338055 <i>Astrophys. J., Vol. 470 (October 1996), 551.</i><br /><br /><img src="http://adsabs.harvard.edu/articles/abstracts/1996/ApJ../1996ApJ...470..551D.gif"><p> Radiative Torques on Interstellar Grains. I. Superthermal Spin-up BT Draine JC Weingartner doi:10.1086/177887 Astrophys. J., Vol. 470 (October 1996), 551. 2008-02-06T01:00:25-00:00 1996 Astrophys. J. 470 551 grains interstellar optical radiation theory torque http://www.citeulike.org/user/rodney/article/2337991 <i>Physical Review A, Vol. 47, No. 2. (February 1993), 1278.</i><br /><br />A theory of radiation pressure and its effects on the gross motion of an aggregrate of charges is established within a canonical framework. The theory indicates the existence of radiation-pressure effects arising from an additional interaction–the Röntgen interaction–whose origin is the classical Röntgen current. A careful development of the formalism reveals the importance of distinguishing between the canonical and mechanical momenta of the gross motion of the aggregate and of incorporating the Röntgen-type interaction terms when calculating the gross-motion dynamics. A form of the Röntgen interaction is present even in the dipole approximation: an effect which has previously been ignored but which is necessary to ensure gauge invariance of the radiation-induced mechanical force. Explicit calculations of the rates of change of canonical and mechanical momenta are presented for a general atomic dipole; with specializations to a two-level atom; revealing the presence of velocity-dependent terms in a natural way. The formalism is consistent with the Minkowski form of the classical momentum density of an electromagnetic field. Canonical approach to photon pressure C Baxter M Babiker R Loudon doi:10.1103/PhysRevA.47.1278 Physical Review A, Vol. 47, No. 2. (February 1993), 1278. 2008-02-06T00:36:31-00:00 1993 Physical Review A 47 2 1278 American Physical Society optical photon pressure radiation theory tweezers http://www.citeulike.org/user/rodney/article/2333093 <i>Physical Review Letters, Vol. 57, No. 3. (21 July 1986), 310.</i><br /><br />We show that the optical Earnshaw theorem does not always apply to atoms and that it is possible to confine atoms by spontaneous light forces produced by static laser beams. A necessary condition for such traps is that the atomic transition rate cannot depend only on the light intensity. We give several general approaches by which this condition can be met and present a number of specific trap designs illustrating these approaches. These traps have depths on the order of a kelvin and volumes of several cubic centimeters. Light Traps Using Spontaneous Forces DE Pritchard EL Raab V Bagnato CE Wieman RN Watts doi:10.1103/PhysRevLett.57.310 Physical Review Letters, Vol. 57, No. 3. (21 July 1986), 310. 2008-02-05T03:04:33-00:00 1986 Physical Review Letters 57 3 310 American Physical Society force optical radiation spontaneous trap tweezers http://www.citeulike.org/user/rodney/article/1222253 <i>Physical Review A, Vol. 21, No. 5. (May 1980), 1606.</i><br /><br />The force exerted by optical-frequency radiation on neutral atoms can be quite substantial; particularly in the neighborhood of an atomic resonance line. In this paper we derive from quantum theory the optical force; its first-order velocity dependence; and its fluctuations for arbitrary light intensity; and apply the results to the problem of creating a stable optical trap for sodium atoms. New results include the position dependence of the velocity-dependent force; a complete expression for the momentum diffusion constant including the substantial contribution from fluctuations of the dipole force; and an estimate of trapping times in excess of 1 sec even in the absence of effective damping. The paper concludes with a discussion of the prospects and difficulties in providing sufficient damping to stabilize such a trap. Motion of atoms in a radiation trap JP Gordon A Ashkin doi:10.1103/PhysRevA.21.1606 Physical Review A, Vol. 21, No. 5. (May 1980), 1606. 2007-04-12T13:30:02-00:00 1980 Physical Review A 21 5 1606 American Physical Society atoms optical pressure radiation trap tweezers http://www.citeulike.org/user/rodney/article/2333031 <i>Physical Review Letters, Vol. 41, No. 20. (13 November 1978), 1361.</i><br /><br />For sodium atoms in an atomic beam; we demonstrate focusing; defocusing; and steering caused by the transverse dipole forces exerted by the radial intensity gradient of a superimposed and co-propagating resonant cw light beam. Dipole radiation-pressure forces differ from the forces due to spontaneous emission and are needed to achieve optical traps for neutral atoms. Observation of Focusing of Neutral Atoms by the Dipole Forces of Resonance-Radiation Pressure JE Bjorkholm RR Freeman A Ashkin DB Pearson doi:10.1103/PhysRevLett.41.1361 Physical Review Letters, Vol. 41, No. 20. (13 November 1978), 1361. 2008-02-05T02:43:05-00:00 1978 Physical Review Letters 41 20 1361 American Physical Society atoms dipole focus neutral optical pressure radiation resonance trap tweezers http://www.citeulike.org/user/rodney/article/2333023 <i>Physical Review Letters, Vol. 40, No. 12. (20 March 1978), 729.</i><br /><br />A method of stably trapping; cooling; and manipulating atoms on a continuous-wave basis is proposed using resonance radiation pressure forces. Use of highly focused laser beams and atomic beam injection should give a very deep trap for confining single atoms or gases at temperatures ∼ 10 -6 °K. An analysis of the saturation properties of radiation pressure forces is given. Trapping of Atoms by Resonance Radiation Pressure A Ashkin doi:10.1103/PhysRevLett.40.729 Physical Review Letters, Vol. 40, No. 12. (20 March 1978), 729. 2008-02-05T02:40:54-00:00 1978 Physical Review Letters 40 12 729 American Physical Society atoms optical pressure radiation resonance trap tweezers http://www.citeulike.org/user/rodney/article/2333018 <i>Physical Review A, Vol. 8, No. 1. (July 1973), 14.</i><br /><br />There has existed a continuing dialogue concerning the proper identification of radiation forces and momenta in dielectric media. I argue herein that a sensible and consistent picture of these forces and momenta is available. That is; the density of electromagnetic momentum G → is given by G →= S → / c 2 ; where S → is Poynting's vector. The forces which are exerted on material objects in dielectric media are associated with changes in both the electromagnetic and mechanical momenta of the media. In fairly broad circumstances; such forces may be found from the rate of change in a pseudomomentum K → given by K →=ε G →; where ε is the dielectric constant of the medium. Radiation Forces and Momenta in Dielectric Media James Gordon doi:10.1103/PhysRevA.8.14 Physical Review A, Vol. 8, No. 1. (July 1973), 14. 2008-02-05T02:39:02-00:00 1973 Physical Review A 8 1 14 American Physical Society dielectric forces optical radiation trap tweezers http://www.citeulike.org/user/rodney/article/2333014 <i>Physical Review Letters, Vol. 25, No. 19. (November 1970), 1321.</i><br /><br />It is proposed to use the saturated value of the radiation pressure force on neutral atoms to produce a constant central force field to deflect atoms in circular orbits and make a high-resolution velocity analyzer. This is useful for studying the interaction of atoms with high-intensity monochromatic light; and to separate; velocity analyze; or trap neutral atoms of specific isotopic species or hyperfine level. Atomic-Beam Deflection by Resonance-Radiation Pressure A Ashkin doi:10.1103/PhysRevLett.25.1321 Physical Review Letters, Vol. 25, No. 19. (November 1970), 1321. 2008-02-05T02:37:15-00:00 1970 Physical Review Letters 25 19 1321 American Physical Society atoms deflection optical pressure radiation trap tweezers http://www.citeulike.org/user/rodney/article/2330027 <i>Physical Review Letters, Vol. 24, No. 4. (26 January 1970), 156.</i><br /><br />Micron-sized particles have been accelerated and trapped in stable optical potential wells using only the force of radiation pressure from a continuous laser. It is hypothesized that similar accelerations and trapping are possible with atoms and molecules using laser light tuned to specific optical transitions. The implications for isotope separation and other applications of physical interest are discussed. Acceleration and Trapping of Particles by Radiation Pressure A Ashkin doi:10.1103/PhysRevLett.24.156 Physical Review Letters, Vol. 24, No. 4. (26 January 1970), 156. 2008-02-04T16:54:48-00:00 1970 Physical Review Letters 24 4 156 American Physical Society optical pressure radiation trap tweezers http://www.citeulike.org/user/rodney/article/2224023 <i>Opt. Lett., Vol. 27, No. 24. (15 December 2002), pp. 2149-2151.</i><br /><br />Multiple scattering calculations of the electromagnetic force and the potential energy exerted by an evanescent field on a nanometric cylinder over a dielectric interface, as well as by a propagating Gaussian beam, are carried out. These calculations constitute a model that describes the gradient, scattering, and absorption components of the force in an elongated particle. The attractive or repulsive nature of the force is strongly dependent on the polarization of the incident field for a metallic particle, whereas a dielectric particle is only weakly attracted to high-intensity regions. Excitation of plasmon resonance in a metallic particle enhances both the scattering and the absorption components of the force, whereas it diminishes the gradient-force component. Radiation pressure over dielectric and metallic nanocylinders on surfaces: polarization dependence and plasmon resonance conditions JR Arias-González M Nieto-Vesperinas Opt. Lett., Vol. 27, No. 24. (15 December 2002), pp. 2149-2151. 2008-01-13T02:06:50-00:00 2002 Opt. Lett. 27 24 2149 2151 OSA cylinders dielectric metal optical plasmons polarization pressure radiation resonance surface trap tweezers http://www.citeulike.org/user/rodney/article/2223991 <i>Opt. Lett., Vol. 25, No. 18. (2000), pp. 1385-1387.</i><br /><br />Radiation pressure induced by an evanescent field was experimentally analyzed for a single submicrometer-sized gold particle. The force measurement was based on a thermodynamic analysis of Brownian motion by use of a three-dimensional position-sensing technique. The lateral radiation pressure could be ascribed to a scattering force, which was oriented in the same direction as the propagation vector of the incident laser beam. The potential profile in the longitudinal direction indicated that the gold particle was attracted to the high-intensity region of the evanescent field by a gradient force. Analysis of radiation pressure exerted on a metallic particle within an evanescent field Keiji Sasaki Jun-Ichi Hotta Ken-Ichiro Wada Hiroshi Masuhara Opt. Lett., Vol. 25, No. 18. (2000), pp. 1385-1387. 2008-01-13T01:49:01-00:00 2000 Opt. Lett. 25 18 1385 1387 OSA evanescent forces laser metal optical pressure radiation trap tweezers http://www.citeulike.org/user/rodney/article/2182630 <i>Optics Communications, Vol. 124 (February 1996), pp. 529-541.</i><br /><br /><A HREF="/cgi-bin/nph-data_query?link_type=EJOURNAL&bibcode=1996OptCo.124..529H">Electronic Article Available</A> from <A HREF="http://www.elsevier.com">Elsevier Science.</A> Radiation forces on a dielectric sphere in the Rayleigh scattering regime Y Harada T Asakura Optics Communications, Vol. 124 (February 1996), pp. 529-541. 2007-12-31T05:58:06-00:00 1996 Optics Communications 124 529 541 dielectric forces optical radiation rayleigh regime scattering trap tweezers http://www.citeulike.org/user/rodney/article/2160212 <i>Langmuir, Vol. 6, No. 7. (1990), pp. 1260-1265.</i><br /><br />We have previously show how total internal reflection microscopy and radiation pressure forces can be used to study weak interactions between particles and surfaces. The work described here illustrates how we have improved the experiment and extended the technique to measure absolute particle-surface separations as a function of NaCl electrolyte concentration. In so doing, we have shown how the dynamics of particles moving orthogonal to a plane surface can be studied. © 1990 American Chemical Society. Measurement of absolute particle-surface separation using total internal reflection microscopy and radiation pressure forces MA Brown EJ Staples Langmuir, Vol. 6, No. 7. (1990), pp. 1260-1265. 2007-12-22T23:04:04-00:00 1990 Langmuir 6 7 1260 1265 microsphere optical pressure radiation surface tirf trap tweezers http://www.citeulike.org/user/rodney/article/1616667 <i>Jpn J Appl Phys Part 1 Regul Pap Short Note Rev Pap, Vol. 31, No. 9 A. (1992), pp. 2954-2958.</i><br /><br />To explore the applicability of synchrotron radiation X-ray lithography for fabricating sub-quartermicron devices, we investigate the patterning characteristics of the chemically-amplified negative resist SAL601-ER7. Since these characteristics depend strongly on the conditions of the chemical amplification process, the effects of post-exposure baking and developing conditions on sensitivity and resolution are examined. The resolution-limiting factors are investigated, revealing that pattern collapse during the development process and fog caused by Fresnel diffraction, photo-electron scattering, and acid diffusion in the resist determine the resolution and the maximum aspect ratio of the lines and spaces pattern. Using the model of a swaying beam supported at one end, it is shown that pattern collapse depends on the resist pattern's flexural stiffness. Patterning stability, which depends on the delay time between exposure and baking, is also discussed. Patterning characteristics of a chemically-amplified negative resist in synchrotron radiation lithography Kimiyoshi Deguchi Kazunori Miyoshi Tetsuyoshi Ishii Tadahito Matsuda Jpn J Appl Phys Part 1 Regul Pap Short Note Rev Pap, Vol. 31, No. 9 A. (1992), pp. 2954-2958. 2007-09-03T20:06:08-00:00 1992 Jpn J Appl Phys Part 1 Regul Pap Short Note Rev Pap 31 9 A 2954 2958 amplified chemically collapse fabrication lithography negative pattern photolithography photoresist radiation resist synchotron http://www.citeulike.org/user/rodney/article/1590555 <i>J Lumin, Vol. 108, No. 1-4., pp. 351-354.</i><br /><br />We derive analytical expressions for the radiation force induced by electronically resonant light which apply over the size range from atoms to nanoparticles. These are based on the method of Maxwell stress tensor and microscopic response theory. The radiation force is expressed as a sum of a scattering force, an absorbing force and additional terms arising from the asymmetric spatial distribution of the internal field from light-exciton coupled modes. In the case of a particle with a radius of few tens of nm, a particular interesting point is that, under certain conditions, substantially large contributions from these terms appear as forces in opposite direction to the direction of propagation of plane wave light. © 2004 Elsevier B.V. All rights reserved. Radiation force induced by resonant light: From atom to nanoparticle T Iida H Ishihara R Reeves G Jones R Syme K Hoffman doi:10.1016/j.jlumin.2004.01.074 J Lumin, Vol. 108, No. 1-4., pp. 351-354. 2007-08-24T18:59:44-00:00 J Lumin 108 1-4 351 354 forces nanoparitcles optical radiation resonance trap tweezers http://www.citeulike.org/user/rodney/article/1552568 <i>J. Korean Phys. Soc., Vol. 35, No. 3. (1999), pp. 180-185.</i><br /><br />We investigate theoretically the optical pressure acting on a dielectric film in a surface-plasmon-coupled evanescent wave which is produced near the surface of a thin metal-coated prism illuminated by a p-polarized plane electromagnetic wave. We show that the pressure arising from the surface-plasmon-coupled evanescent waves in a metal-coated multilayer system is about ten times as large as that on the surface of a bare dielectric prism. The evanescent field pressure has a potential application in manipulating or sorting a planar-type particle near the surface of a thin metal. Enhancement of the evanescent field pressure on a dielectric film by coupling with surface plasmons BM Han S Chang SS Lee J. Korean Phys. Soc., Vol. 35, No. 3. (1999), pp. 180-185. 2007-08-10T21:38:07-00:00 1999 J. Korean Phys. Soc. 35 3 180 185 dielectric enhancement evanescent film plasmons pressure radiation spr surface tirf http://www.citeulike.org/user/rodney/article/1552563 <i>Jpn J Appl Phys Part 1 Regul Pap Short Note Rev Pap, Vol. 32, No. 4. (1993), pp. 1642-1650.</i><br /><br />We investigate the radiation torque exerted on a rotating dielectric sphere in a focused Gaussian beam. In the (inertial) laboratory frame we solve the relativistic scattering problem for the Gaussian beam incident on a rotating sphere by including correction terms of up to first-order in angular velocities. We then derive the analytical formulas of the radiation torque within the framework of a scattering theory and discuss and derived results in comparison with our earlier works for a stationary sphere. Numerical results show that the ratio of the first-order correction to the zeroth-order torque is about 0.2 × 10-2 at the highest rotational frequency. Radiation torque exerted on a rotating sphere in a focused Gaussian laser beam: first-order correction in angular velocities Soo Chang Sang Lee Jpn J Appl Phys Part 1 Regul Pap Short Note Rev Pap, Vol. 32, No. 4. (1993), pp. 1642-1650. 2007-08-10T21:32:15-00:00 1993 Jpn J Appl Phys Part 1 Regul Pap Short Note Rev Pap 32 4 1642 1650 angular first-order gaussian laser optical radiation rotation sphere torque trap tweezers velocity http://www.citeulike.org/user/rodney/article/1446485 <i>Applied Physics Letters, Vol. 67 (October 1995), pp. 2269-2271.</i><br /><br />Not Available Ray optics model and numerical computations for the radiation pressure micromotor RC Gauthier Applied Physics Letters, Vol. 67 (October 1995), pp. 2269-2271. 2007-07-10T12:34:08-00:00 1995 Applied Physics Letters 67 2269 2271 micromotor numerical optical pressure radiation rayoptics simulation tweezers http://www.citeulike.org/user/rodney/article/1397567 <i>Journal of Applied Physics, Vol. 66, No. 10. (1989), pp. 4594-4602.</i><br /><br />Series expressions for the net radiation force and torque for a spherical particle illuminated by an arbitrarily defined monochromatic beam are derived utilizing the spherical-particle/arbitrary-beam interaction theory developed in an earlier paper. Calculations of net force and torque are presented for a 5-µm-diam water droplet in air optically levitated by a tightly focused (2 µm beam waist diameter) TEM00-mode argon-ion (=0.5145 µm) laser beam for on and off propagation axis, and on and off structural resonance conditions. Several features of these theoretical results are related to corresponding experimental observations. Journal of Applied Physics is copyrighted by The American Institute of Physics. Theoretical determination of net radiation force and torque for a spherical particle illuminated by a focused laser beam JP Barton DR Alexander SA Schaub doi:10.1063/1.343813 Journal of Applied Physics, Vol. 66, No. 10. (1989), pp. 4594-4602. 2007-06-18T20:43:09-00:00 1989 Journal of Applied Physics 66 10 4594 4602 AIP focus forces laser optical particles radiation spherical theory torque tweezers http://www.citeulike.org/user/rodney/article/1199051 <i>Physical Review Letters, Vol. 48, No. 14. (5 April 1982), 957.</i><br /><br />Theoretical calculations are presented which show that the enhancement predicted by the particle plasmon model of surface-enhanced Raman scattering is limited by radiation damping. The damping becomes more severe as particle size increases; while the enhancement produced by small particles is limited by surface scattering. Good agreement between theory and experimental measurements of the wavelength dependence of surface-enhanced Raman scattering on lithographically produced microstructures is found when radiation damping is taken into account. Radiation Damping in Surface-Enhanced Raman Scattering A Wokaun JP Gordon PF Liao doi:10.1103/PhysRevLett.48.957 Physical Review Letters, Vol. 48, No. 14. (5 April 1982), 957. 2007-03-30T23:56:45-00:00 1982 Physical Review Letters 48 14 957 American Physical Society damping enhancement radiation raman scattering surface http://www.citeulike.org/user/rodney/article/1181352 <i>J Phys Chem B, Vol. 106, No. 5. (2002), pp. 905-909.</i><br /><br />Laser manipulation and laser trapping techniques were applied to ?m sized gel-like wire-type dendrimer (L3PPE130 and L4PPE8) assemblies, which are formed at drying process of their tetrahydrofuran (THF) solution on a glass substrate. Deformation and extension of single gel-like assemblies were demonstrated with irradiation of a focused 1064 nm laser beam by scanning a microscope stage. In repetitive irradiation experiments, contraction and swelling of the gel-like assembly were observed in response to the switch on and off of the laser beam, respectively, and in the case of the L3PPE130 gel-like assembly, fluorescence spectra detected at a focal point changed accompanying the contraction and swelling behavior. This spectral change means molecular aggregates were formed transiently by photon pressure of the focused near-infrared laser beam. Repetitive contraction and swelling behavior of gel-like wire-type dendrimer assemblies in solution layer by photon pressure of a focused near-infrared laser beam S Masuo H Yoshikawa T Asahi H Masuhara T Sato DL Jiang T Aida doi:10.1021/jp013367e J Phys Chem B, Vol. 106, No. 5. (2002), pp. 905-909. 2007-03-23T05:35:09-00:00 2002 J Phys Chem B 106 5 905 909 assembly dendrimer focus gel near-infrared optical pressure radiation tweezers http://www.citeulike.org/user/rodney/article/1181347 <i>J. AM. CHEM. SOC., Vol. 119, No. 11. (1997), pp. 2741-2742.</i> Molecular association by the radiation pressure of a focused laser beam: Fluorescence characterization of pyrene-labeled PNIPAM J Hofkens J Hotta K Sasaki H Masuhara T Taniguchi T Miyashita doi:10.1021/ja963830e J. AM. CHEM. SOC., Vol. 119, No. 11. (1997), pp. 2741-2742. 2007-03-23T05:29:59-00:00 1997 J. AM. CHEM. SOC. 119 11 2741 2742 assembly flyuorescence focus pressure pyrene radiation http://www.citeulike.org/user/rodney/article/1181336 <i>J Phys Chem B, Vol. 109, No. 15. (2005), pp. 7033-7039.</i><br /><br />We developed a confocal Raman microspectroscopy system combined with a laser trapping technique and applied it to aqueous solutions (H2O and D2O) of poly(N-isopropylacrylamide) (PNIPA), which is well-known as a representative thermo-responsive polymer, i.e., phase transition/separation between coiled and globular states. By introducing a near-infrared (1064 nm) laser beam into a microscope, PNIPA microparticles were produced at the focused spot of the laser beam, both in H2O and D2O. By using the present system, we succeeded in obtaining the Raman spectra of PNIPA in the coiled and globular states over a wide wavenumber region (800-3500 cm -1) for the first time. For the D2O solutions (in which the photothermal effect is negligible and hence the microparticles should be produced purely by the effect of radiation pressure), some significant differences were observed in the Raman spectra for the coiled state, in the globular state, and for laser induced microparticles. By analyzing these spectra in detail, we revealed that the structure of the laser-induced microparticles was analogous to that in the globular state. We also discuss the fundamental mechanism underlying the transformation of the higher order structure of a polymer by radiation pressure. © 2005 American Chemical Society. Poly(N-isopropylacrylamide) microparticles produced by radiation pressure of a focused laser beam: A structural analysis by confocal Raman microspectroscopy combined with a laser-trapping technique Y Tsuboi M Nishino T Sasaki N Kitamura doi:10.1021/jp044894b J Phys Chem B, Vol. 109, No. 15. (2005), pp. 7033-7039. 2007-03-23T05:01:42-00:00 2005 J Phys Chem B 109 15 7033 7039 assembly confocal focus microparticles optical pressure radiation raman spectroscopy tweezers http://www.citeulike.org/user/rodney/article/1181335 <i>Langmuir, Vol. 13, No. 3. (1997), pp. 414-419.</i><br /><br />Phase transitions in aqueous solutions of poly(N-isopropylacrylamide) (PNIPAM) with a molecular weight (Mw) of 63 000 were achieved by irradiating the solutions (0.2-3.6 wt %) with an IR laser beam (1064 nm) through an optical microscope. First, a microparticle with the size of the focused laser beam was formed (?1.5 ?m). This microparticle continuously grew and after prolonged irradiation (up to 10 min), a microparticle with a maximum size of 25 ?m was obtained. Upon further irradiation, the microparticle became unstable and finally disappeared. The importance of the optical alignment of the microscope/laser system is discussed. Particle formation was also found in D2O solutions of PNIPAM. These experimental results indicate that, besides a photothermal effect (heating up of the solution due to absorption of water at 1064 nm), there is influence of the "radiation force" upon particle formation and conformation properties of the polymer. The observations mentioned above are discussed in connection with the theory of the single beam gradient force optical trap for dielectric particles. Molecular assembling by the radiation pressure of a focused laser beam: Poly(N-isopropylacrylamide) in aqueous solution J Hofkens J Hotta K Sasaki H Masuhara K Iwai Langmuir, Vol. 13, No. 3. (1997), pp. 414-419. 2007-03-23T04:57:01-00:00 1997 Langmuir 13 3 414 419 assembly focus pressure radiation http://www.citeulike.org/user/rodney/article/1179104 <i>Science, Vol. 210, No. 4474. (5 December 1980), pp. 1081-1088.</i><br /><br />Use of lasers has revolutionized the study and applications of radiation pressure. Light forces have been achieved which strongly affect the dynamics of individual small particles. It is now possible to optically accelerate, slow, stably trap, and manipulate micrometer-sized dielectric particles and atoms. This leads to a diversity of new scientific and practical applications in fields where small particles play a role, such as light scattering, cloud physics, aerosol science, atomic physics, quantum optics, and high-resolution spectroscopy. 10.1126/science.210.4474.1081 Applications of Laser Radiation Pressure A Ashkin doi:10.1126/science.210.4474.1081 Science, Vol. 210, No. 4474. (5 December 1980), pp. 1081-1088. 2007-03-21T14:12:11-00:00 1980 Science 210 4474 1081 1088 optical pressure radiation tweezers