Investigation Of Light Propagation And Imaging Beyond The Diffraction Limit Based On Surface Plasmon

Diffraction is one important physical and inherent property associated with light.Suffering from the light diffraction feature, it is hard for conventional optics tomanipulate light propagation, focusing and imaging in spaces with dimensions farbeyond the wavelength. With the fast development of modern science and technology,optics&electronics devices, microscope, lithography and optical storage usuallyrequire much smaller dimensions, higher density and higher resolution. The diffractionlimit, however, imposes an obstacle for improving spatial resolution of modern optics.In recent years, a great deal of investigations showed that surface plasmon (SP)possesses some abnormal characteristics, like propagation with short wavelength,evanescent waves coupling and amplification etc, delivering one access to break thediffraction limit.Presented in the Dissertation are our investigation of methods for light propagationand imaging beyond the diffraction limit by using of surface plasmon, including themechanism of surface Plasmon excitation and its influence for light emission behaviors,formalism and model of light propagation inside metamaterial, principles and methodsfor designing optical devices with subwavelength resolution and lithographyexperiments. The main achievements are listed below.1. Within the framework of Kirchoff’s diffraction theory, refined model ispresented for surface plasmon excitation and light beaming from sub-wavelength slitflanked by periodic grooves structures. The accuracy of the formalism is demonstratedwith numerical and experiment results. Deep insights of the influences of groovesstructure for the beaming behaviors are given as well.2. Theoretical and experimental investigations are performed for light propagationinside metamaterial composed by alternatively stacked metal and dielectric films,directive propagation of light behaviors are first experimentally observed in the far field. And comparisons are given for calculation results by variant methods, like EMT, RCWAand FEM.3. Surface plasmon resonance and amplification of evanescent waves for multimetal and dielectric films system are investigated. The formalism of super lens is thengeneralized into anisotropic structure.4. By employing the effective medium theory and metamaterial, subwavelengthimaging formalisms with multi metal and dielectric films are investigated withanalytical optical transfer functions and comparison for five types of sub-wavelengthimaging with metal and dielectric films.5. A method for super resolution imaging in the far field is proposed with the helpof metallic grating structures. Simplified formalism and numerical simulations show theminimum resolving power of about45nm half pitch (about1/8wavelength) asdemonstrated by numerical simulations.6. Reflective plasmonic lens lithography method is proposed and investigated forits improvement of imaging contrast and elongated depth inside photo resist layer.Experiment demonstrations are presented with i-line mercury lamp with365nmwavelength and the available minimum half pitch resolution is about30nm (~1/12wavelength).