ii In this thesis the in-plane pattern distortion resulting from the use of Evanescent Near Field Optical Lithography (ENFOL) masks was investigated. ENFOL is a high resolution low-cost technique of lithography that is able to pattern features beyond the diffraction limit of light. Due to its use of the evanescent near field, ENFOL requires the use of conformable masks for intimate contact. Such masks can stretch and skew as they come into contact with silicon substrates and therefore distort the high resolution features patterned on them. It was desired to measure this distortion to ascertain the patterning performance of ENFOL masks and possibly correct for any uniform distortion found. To this end a sophisticated measuring process was successfully demonstrated. This involved the use of a Raith 150 Electron Beam Lithography (EBL) system with precision laser interferometer stage and metrology software module for automated measurements. Custom software was written for the Raith to enable it to take

Transfer-matrix and finite element modelling techniques were used to simulate single- and multi-layer silver-based superlenses. The techniques were compared for their abilities to simulate sub-diffraction-limited resolution and DC transmission. The finite element modelling technique confirmed conclusions drawn from T-matrix analysis, namely that multi-layer superlenses had greater transmission over a larger window of spatial frequencies than single-layer superlenses and that superlens performance was adversely affected by resonances at different frequencies. The failure of the T-matrix technique to model interactions between the mask and lens was identified as one of the main sources of inaccuracy; however, the technique remained valuable due to its superior computational efficiency compared to finite element modelling. Keywords-superlens; near-field imaging; simulation tools. I.