Research On Technologies Of Curved Optical Component Fabrication By Flexible Nanoimprint Lithography

Compared with traditional planar optical elements,curved optical elements have great advantages in function integration,device volume and so on,widely used in the fields of micro imaging module,micro spectrometer and so on.The traditional fabricating method of curved optical elements is technically challenging and high cost,which becomes the bottleneck of its mass production.However,with the development of nanoimprinting technology,especially flexible nano-imprinting technology,it is possible to fabricate curved optical elements with low cost and high efficiency.Therefore,this paper research on a method of curved optical components fabrication based on flexible nanoimprinting technology,that is,using flexible mold instead of traditional hard mold,using ultraviolet nanoimprinting technology,by vacuum negative pressure method to achieve low-cost and high-efficiency fabrication of curved optical elements.A set of fully automatic flexible nanoimprinting equipment was developed to control the imprinting pressure,imprinting time and ultraviolet exposure accurately.Meanwhile,uniform pressure and clean environment were provided.Taking a typical curved optical element—the varied-line-space concave blazed grating as the processing target,and studying the flexible nanoimprint lithography technology.The expansion and deformation law of PDMS soft template is studied theoretically and simulated.On this basis,the optimal parameters were selected for grating fabrication.The morphology,spectral resolution and diffraction efficiency of the final imprinting grating were tested and analyzed,and it was found that the geometric parameters were consistent with the theoretical prediction,and the optical properties reached the expected goal,which proves the reliability and the feasibility of the flexible nanoimprint lithography equipment and technology of this paper.