Principle And Methodological Investgation On Deep Wavelength Imaging Based On Hyperbolic Metamaterial

Super-resolution optical imaging is one of the major research goals of modern optics.Evanescent waves having higher frequencies may work as a light source for the super-resolution imaging.However,due to the rapid decaying property,evanescent waves are unable to be used for the imaging process.Surface plasmons?SP?can couple or amplify evanescent waves with higher vectors,thus enabling the manipulation of amplitude and phase of the evanescent waves.With the SPs,it is possible to use the evanescent waves for the imaging.Many structures,like one single metal layer and metal-dielectric multilayers,have been proposed and fabricated to engineering the SPs to achieve high resolution optical imaging.In this thesis,principle and method of subwavelength imaging by the SP waves engineered by the hyperbolic metamateials have been investigated.Details are listed in the following.1.Investigation of enhancement of near-field imaging by structured bulk plasmon illumination?BPI?source.According to the principles of light propagation and optical spatial spectrum filtering in the layered metal–dielectric structure,multilayered Al/MgF₂ and ZrO₂/Al structures are designed for lithography and optical imaging.An enhanced near-field bulk Plasmon illumination is achieved by the coupling of SPs between the Ag layers.For plasmonics cavity lens imaging,the intensity of BPI with Ag layer is improved by 30 times over the BPI without Ag layer.When two nano-slits are illuminated by the BPI source,the imaging resolution of plasmonic cavity superlens is improved obviously and imaging intensity is improved 3 times.For surface imaging,the intensity of BPI with Ag layer is improved by 50 times over the BPI without Ag layer and the fluorescent intensity is imporved by 1.46 times when 2um diameter fluorescent beads are illuminated by the BPI source,2.Designing and analysis of deep subwavelength BPI with ultra-short illumination depth.Hyperbolic metamaterials?HMMs?composed of Ag/SiO₂ multilayers are proposed for band-pass filtering.By off-axis illuminating the gratings on the multilayers,the BPI with a tunable ultra-short illumination depth can be designed.The minimum illumination depth is 10nm.As the coupled plasmon modes are over a wide wavevector range in HMMs,the illumination depth could be continuously tuned by simply adjusting the incidence angle of light for the BPP excitation.Illumination depths of 19nm-63nm at a light wavelength of 532 nm are demonstrated with Ag/SiO₂ multifilms.A fluorescent pattern of 27nm thick immersed in the another fluorescent dye was imaged by this surface imaging microscopy and the results indicate that the distinct surface images with high contrast could be obtained under the BPP illumination with ultra-short penetration depth.3.The SP lithographic imaging with negative refraction metamaterial.Negative refraction metamaterials composed of Ag/TiO₂ multilayers are designed for the lithographic imaging.Compared with near-field lithography,the work distance of the metamaterial is elongated to 400nm and gratings pattern with pitch over 360nm can be well imaged.Further work have demonstrated 350nm line resolution with 400nm working distance.