• High-resolution and large-area laser interference nanomanufacturing technology

      Wang, Dapeng (University of BedfordshireUniversity of Bedfordshire, 2014-10)
      The thesis systematically investigates the laser interference nanomanufacturing technology taking into account its advantages and abilities to realise various potential applications. The latest progresses have addressed the major issues hampering the cross-scale developments of structural applications, such as cost-ineffective fabrication, limited area, low efficiency and challenging integration. The studies carried out on high-resolution and large-area laser interference nanomanufacturing technology will complement the exploration of modern optical devices and extraordinary functional applications. With respect to classical interference theory and relevant references, there is still a lack of studies providing insight into the effects of polarisation on the multi-beam interference while it is found that the polarisation vector plays a key role in the formation, period and contrast of interfering patterns. Herein, the theory of multi-beam interference is developed through the integration of the polarisation vector and electric field vector. It is worth pointing out that based on the detailed analysis of the four-beam interference with the special polarisation modes, it is demonstrated that the modulation phenomenon in four-beam laser interference is the result of the misalignment of incident angles or unequal incident angles only in the case of the TE-TE-TM-TM mode. In the experiments, a straightforward method of generating various well-defined structures on material surfaces is proposed using the nanosecond laser interference system. The experimental results of two-, three- and four-beam interference show a good correspondence to the theoretical analyses and simulations. Artificial bio-structures are fabricated using the four-beam interference method with the TE-TE-TE-TE polarisation mode and the fabricated microcone structures exhibit excellent properties with both a high contact angle (CA=156.3°) and low omnidirectional reflectance (5.9-15.4%). In order to fabricate high-resolution structures, the 266nm nanosecond laser interference system is employed to treat the organic and metal-film materials. Nanograting structures with feature sizes of sub-100nm width and 2nm height are fabricated on the organic material surface. An attempt is successfully conduced to produce the nanoelectrode arrays by using laser interference lithography and chemical deposition. Finally, the advantages of the developed laser interference technology and contributions of the research are summarised, and recommendations of future work are given.