Study On Photonic Forces On Particles In The Evanescent Interference Field Created By Total Internal Reflection

Near-field optics is a new branch of physical optics, which is the study ofsub-wavelength away from the object’s surface within the optical field distribution. Itstudies mainly the evanescent wave to obtain object’s refined structural information.As a result, the optical resolution based on the near-field optical technology isnanometer order of magnitude. With the continuous development of the near-fieldoptics theory and the improvement of the near-field optical microscopy system, thenear-field optics is applied and developed in physics, materials, biology, information,medical and other areas.Firstly, the paper introduces the development of near-field optics, ultra-resolutiondiffraction theory, near-field optical microscopy structure of the system andapplications. Secondly, a brief introduction of basic theory of the near-field optics ispresented, such as finite-difference time-domain (FDTD), scattering perturbationtheory, complex multi-pole method, Green function method and the theory of dyadicpropagator. Again, the horizontal and vertical distribution of the dipole radiationwithin near-field is analyzed based on the dipole model. And the theory of multiplescattering from the dipole to obtain optical resolution based on a half width. Thenear-field optical coupling is theoretical discussed on the image method. A generalcharacteristic of the near-field optical microscope resolution is obtained from thenumerical analysis. The interaction between light and matter is analysis in-depth.Finally, a new type of pyramidal prism is constructed. The evanescent field andinterference evanescent field that formed by total internal reflection on the surface ofthe prism and its propagation characteristics are discussed. Gaussian beam as a lightsource, the distribution of one-dimensional and two-dimensional interference field areobtained theoretically. The photonic force of nanometer particles in the potential ofevanescent interference field is obtained theoretically. The photonic force consists ofweaker scattering force and strong gradient force. With the numerical calculation, wecan find that evanescent wave interference field will increase the scope of the role ofoptical power to enhance the role of optical power intensity in comparison withordinary evanescent field. The linear chain of particles is formed in the1-Dinterference evanescent field, and the steady equilibrium positions are achieved in anarray in the2-D interference evanescent field. End of the paper used the ray optics model to devote oneself to the brief introduction to the Mie granule in Gaussian lightbeam optics.The results above mentioned not only make for us to understand thecharacteristics of the near-field optics further, but also provide theoretical referencefor the developing new type near-field detector and so on.