Large-area Fabrication Of Periodic Micro/Nano Patterns Based On Oswald Ripening In Laser Interference Field

Laser interference lithography(LIL)technology is a periodic or quasi-periodic light field distribution generated by laser interference,which directly or indirectly acts on the surface of materials to create controllable micro/nano patterns.The interference pattern can be directly ablated on the surface of the sample by a laser;it can also be recorded on the photoresist first,and then transferred to the surface of the sample through electroplating,etching and other processes to generate micro/nano patterns.Laser direct writing technology is a precise laser writing technology,which has the advantages of no mask,high precision,high production efficiency,low cost,and flexible processing.In this paper,a direct laser interference lithography system without photoresist is designed,which simplifies the lithography process.By controlling the Gaussian interference lithography beam pulse energy,exposure time,coating thickness and other parameters,the silver-silicon(Ag@Si)material system is optimized.Micro/nano structure anti-reflection,structural color and other surface characteristics,mainly through double beam single exposure,double beam double exposure laser interference lithography technology,using the mass transfer brought by Oswald aging to control the thermal dehumidification process.In order to achieve the purpose of controllable preparation of periodic gradient micro/nano patterns,the purpose is to analyze the controllability of particle size and distribution in the process of laser interference direct writing.Combining a French nanosecond pulsed high-power laser with a wavelength of 355 nm and a five-axis displacement platform,the large-area splicing of periodic micro/nano patterns was realized.A large-area micro/nano lattice structure with a period of 2 μm controllably arranged,and the particle size is proportional to the thickness of the coating.The prepared periodic micro/nano structure was characterized,and the reflectivity of the micro/nano structure was measured by angle-resolved spectroscopic microscopy(ARM),and the effect of the micro/nano structure functional surface on the optical properties was studied.The experimental results show that,compared with the untreated samples whose reflectivity does not change with the observation angle,the reflectivity of the samples after interference lithography changes significantly with the change of the observation angle,indicating that the samples processed by interference lithography have the characteristics of structural color,and the color contrast of the sample structure is positively correlated with the regularity of the sample array structure,while the average reflectance of the sample is negatively correlated with the particle size of the micro/nano structure.Large-area-size controllable periodic micro/nano structures have a wide range of applications in solar cells,magnetic storage,photonic crystals and other fields.This work provides a new method for large-area preparation of periodic micro/nano structures.It is expected to realize low-cost,high-efficiency,large-area periodic micro/nano pattern preparation.