The Manipulation And Applications Of Optical Surface Wave

Optical surface waves are electromagnetic waves bound to the surface of a material,which exist in various forms,such as evanescence waves at total internal reflection interface,surface plasmonic polaritons at noble metal/dielectric interface,the Bloch surface waves in the defect layer of dielectric multilayer structure.Optical surface waves can be manipulated in the plane and have the unique electromagnetic properties,including surface electric field enhancement,sensitivity to the permittivity of the environment and propagation with subwavelength confinement,which make them find broad applications in manipulation of surface optical field,surface-enhanced Raman scattering,dark field imaging,optical tweezers,micro/nano photonic devices and high-sensitivity detection.This thesis briefly introduces the electromagnetic properties of optical surface waves and the leakage radiation microscope,and mainly studies the manipulation of one-dimensional surface plasmonic waves,optical trapping in focused Bloch surface waves and thermal trapping in focused plasmonic waves on gold film.The main research works and conclusions are as following:1.For one-dimensional surface plasmonic polaritons propagating along sliver nanowires,a dielectric multilayer with a photonic band gap is used as the substrate.Photonic forbidden band can inhibit the leakage radiation and decrease the leakage loss of the propagating optical field,which can greatly extend the propagation distance of one-dimensional surface plasmonic polaritons.The coupling of one-dimensional surface plasmonic polaritons along silver nanowires and one-dimensional surface Bloch waves along dielectric nanowires on dielectric multilayer substrate is realized by near-field coupling and the coupling efficiency between two one-dimensional surface waves is analyzed by coupled mode theory.Due to sensitivity to the permittivity of the surrounding environment for surface plasmonic polaritons,the propagation parameters of one-dimensional surface plasmonic polaritons can be manipulated by changing the thickness of the top layer of the dielectric multilayer substrate.2.A focused annular azimuthally polarized beam is used as the incident beam to efficiently excite the focused Bloch surface waves.The surface waves on the excitation ring propagate to the focused center and generate strong electric field peaks.In focused surface optical field,the scattering force and the gradient force are both directed to the focused center and the micro-sized metallic particles can be trapped.The optical force acting on metallic particles by Maxwell stress tensor method is calculated to find the equilibrium position.By comparing trapping behaviors by focused Bloch surface waves and focused surface plasmonic polaritons,it demonstrates that the trapping stiffness for focused Bloch surface waves is better than that for focused surface plasmonic polaritons.3.The electric field peaks in the center of focused plasmonic polariton on a gold film can generate strong electromagnetic heat,which will lead to thermal convection in the liquid.The thermal convection can achieve large rang and batch trapping of particles dispersed in the liquid.The numerical simulation of thermal convections in the liquid is performed,which agree well with the experimental results.In the experiment,the comparison with the optical trapping behavior in glass substrate proves that the trapping on gold film is mainly caused by thermal convection.The thermal effect on gold film is demonstrated by the temperature-dependent fluorescence.Highlights of the dissertation are as following:1.Photonic forbidden band of dielectric multilayer substrate is used to decrease the leakage loss of one-dimensional surface plasmonic polaritons,which can greatly extend their propagation distance.This work can broaden the application range of micro/nano photonic devices base on one-dimensional optical surface waves.2.The Coupling of one-dimensional surface plasmonic polaritons along silver nanowires and one-dimensional surface Bloch waves along dielectric nanowires on dielectric multilayer substrate are realized,which may find more opportunities for hybrid photonic integration.3.The propagation parameters of one-dimensional surface plasmonic polaritons can be manipulated by changing the thickness of the top layer of the dielectric multilayer substrate,which is a method of manipulating one-dimensional optical field without damage.4.Realizing the trapping of micro-sized metallic particles by focused Bloch surface waves on a dielectric multilayer substrate.The method does not require high-precision of the relative position between the optical field and the metallic particle and can also avoid the thermal effects in focused plasmonic field on a gold film,which can decrease the trapping stability of optical tweezers.It is a simple and universal method to trapping micro-sized metallic particles.5.Realizing the trapping of particles suspended in the liquid by the thermal convection in focused plasmonic field on a gold film.Due to electric field enhancement of surface plasmonic polaritons and focused effect,an incident beam with a low power can lead to thermal convection,which can achieve large rang and batch trapping of particles.As to optical trapping,thermal convection trapping has unique advantages in the field of life science and crystal preparation.