The Application Of A Novel Plasmonic Probe In Quantum Optics

Surface plasmon has attracted more and more attention in recent years,because it has the ability to break the optical diffraction limit and tightly confine the energy at sub-wavelength scale.This unique property makes it possible for the surface plasmon to reduce the size of integrated devices and improve the integration,which remains a challenge for the optical devices due to the limitation of optical diffraction limit.On the other hand,the ability of electromagnetic field localization can strongly improve the optical density of states,which can also strongly enhance the interaction strength between photons and matter.In the previous works,surface plasmons have been widely studied in integrated optics,quantum information transmission,strong coupling and other applications.Based on the two natural advantages of surface plasmon,my work mainly focused on designing and fabricating a fiber taper-silver nanowire probe,and apply it to near-field optics and quantum optics.This paper mainly consists of five parts as listed in the following:1.The parameters and fabrication process of the fiber taper-silver nanowire near-field probe.We chose the fiber taper with a taper angle of about 6°?7°by mechanically drawing,and a silver nanowire with a radius of about 160nm?250nm coated by silica.The specific fabrication steps were given.2.Analysis and control of different plasmon modes on the probe.Based on the dif-ferent far-field radiation patterns of the fundamental mode and second-order modes of the surface plasmon on metal nanowires,we propose a simple far-field method to mea-sure the scattering light at two orthogonal directions,which requests no precise instru-ments or complicated operations.The excited fundamental and second-order mode can be distinguished when combine the experimental results and simulation results.Fur-thermore,it is found that the SPP modes can be selectively excited by adjusting the coupling length.3.The interaction between the surface plasmon probe and the single photon emit-ters.Materials with different polarizations were used to realize different lifetime mod-ulations:for the single photon emitters oriented perpendicular to the substrate,efficient collection and near-field scanning imaging were acheived,and a significantly reduced lifetime was obtained;for the single photon emitters oriented parallel to the substrate,an increase or decrease of the lifetime has been realized via different relative location between the probe and the emitter.The results show that the probe can locally modulate a single photon source and has strong polarization dependence.4.A feasible scheme to improve the sensitivity and resolution of near-field optical scanning imaging using the SPP probe.In order to improve sensitivity,we used a single photon source to measure the transmittance of the samples,and the SNR was better than that of the laser as the same brightness;in order to improve the resolution,we focused on reducing the resolution degradation caused by high-order mode of silver nanowires in different working modes of near-field optical scanning microscope.We experimental realized a super-resolution optical imaging with 808nm laser.5.We experimentally demonstrated strongly enhanced second harmonic generation in one dimensional heterostructure cavities on thin film lithium niobate.Guided-mode resonance resonator and distributed Bragg reflectors are combined for both efficient coupling and electromagnetic field localization.By adjusting the geometrical parame-ters and optimizing the trade-off between quality factor and mode volume,over 1200 times second-harmonic generation enhancement is experimentally realized.This struc-ture can also be used in other nonlinear processes with low conversion efficiency,such as third harmonic generation,spontaneous parametric down conversion,four wave mix-ing and so on.This novel plasmonic near-field probe introduced here can be used in fluorescence super-resolution imaging,Raman super-resolution imaging and other nano-recognition technologies in the future.At the same time,it can be integrated with single quantum dots or other single-photon emitters to realize a movable single photon source.More super-resolution imaging schemes may be realized after a more detailed design of the probe,to utilize the hollow structure of the SPP mode for instance,and has great appli-cation potential.