Study On The Preparation Of Wide-Band Antireflective Micro/Nano Composite Metal Surface By Nanosecond Laser

The reflective properties of the material surface have great application potential in photonics,electronics,sensing applications,etc.,especially metal materials such as Au,Ag,Pt,Cu,Al,etc.,in photonic,electronic,infrared sensing,radar stealth.Raman spectroscopy detection enhancement and other fields have significant applications and other fields have significant applications.At present,due to the increasing shortage of energy,the sustainability of solar energy and the characteristics of green environmental protection make it one of the most ideal energy sources.The absorption of the solar main radiation band by the reinforcing material is one of the effective ways to enhance the photoelectric and photothermal conversion efficiency.In general,the means for changing the anti-reflective properties of the surface of the material are mainly anti-reflective coatings and anti-reflective structures.In this paper,the micro-nano composite structure with anti-reflective properties on the copper metal surface is induced on the copper surface by nanosecond laser direct writing method.By studying the process of plasma expansion,cooling and deposition in laser ablation,the process of laser induced micro-nano composite structure morphological changes,as well as the composition analysis of the structures,comprehensively analyze the formation mechanism of metal micro/nano composite structures induced by laser;The preparation of micro-nano composite structure is studied,and the absorption rate is detected on different structural surfaces,moreover the relationship between the surface absorption properties,laser processing parameters and surface structure morphology is analyzed.Finally,the temperature and distillation test of the structural samples were carried out by using simulated sunlight.The temperature change,photothermal conversion efficiency and distillation rate of the material were used as performance evaluation criteria to prove the enhancement effect of the micro-nano composite structure on the surface light absorption performance.The specific research methods and conclusions are as follows:(1)ICCD and imaging spectrometer were used to study the dynamic expansion process and spectral information of laser-induced plasma,using microscopic detection to analyze the morphological change process of micro-nano composite structure during processing,and using EDS and XRD to analyze the surface composition of the structure.The results show that High-energy nanosecond pulsed laser acts on the surface of the material,some of the material is removed.And due to plasma expansion and intense heat accumulation,a large amount of molten material is sprayed off the surface and deposited in the processing area,forming a random micron structure.In addition,the laser-induced plasma is restricted by the environmental action in a very small space and have strong interaction with atmospheric molecules to produce metal nano-oxide particles.After the plasma is cooled,it is agglomerated together and deposited by gravity on the surface of the material to form the micro-nano structure.(2)Changing the laser parameters to obtaining the anti-reflective surface with different morphological features,and studying the influence of scanning speed and scanning space on the micro-morphology.The results show that increasing the scanning speed will make the gap between structures larger,and the regular periodic groove structure can be obtained by increasing the scanning spacing.The absorbance of the surface with different structure in the range of 220-2500 nm is measured by a spectrophotometer.The results show that the micro/nano structure can greatly improve the anti-reflection performance of the material surface.Especially in the 220-800 nm band,the rate reaches 98%.And the structural morphology has a great influence on the light absorption performance of the material surface in the near-infrared region.The reasonable size of the micro-structure can effectively increase the anti-reflection of the material surface.By optimization,the average absorbance of the anti-reflective surface at 220-2500 nm is over 90%(the polished copper surface is 19.4%).(3)The Xenon lamp was used simulate the sun,the surface temperature of the structure with different morphological features was tested by light heating and distillation.The results show that the micro-nano composite structure can greatly improve the photothermal conversion efficiency of the surface of the material.The temperature rises rapidly and the performance is obvious.In the distillation experiment,the surface of the anti-reflective structure has a higher photothermal conversion efficiency,which is 1.5-2 times that of the polished sample,and the distillation rate of the structured surface is more than twice that of the polished surface.