研究目的
The problem or phenomenon addressed in this study is the potential of ultrashort laser material processing (ULMP) technique in changing the optical properties of metallic substrates, specifically focusing on the role of laser induced nano/micro structures on the optical features of 316L stainless steel surfaces.
研究成果
The study concludes that ultrashort laser material processing can effectively modify the optical properties of metallic surfaces by creating nano/micro structures. The optical response of these surfaces is anisotropic, depending on the incident angle, polarization of the illuminating light, and surface orientation. The findings suggest potential applications in photonic and optoelectronic technologies where control over backscattering amount and polarization features is needed.
研究不足
The study acknowledges the complexity of analyzing surfaces covered by regular/irregular nano or micro scale structures and the limitations due to diffusive light scatterings or dispersions. The multi-scale nature of the morphologies introduces challenges in predicting the optical response based solely on surface roughness or correlation length.
1:Experimental Design and Method Selection
The study involves the irradiation of 316L stainless steel sheets with a Ti-Sapphire Chirped Pulse Amplified (CPA) femtosecond laser system under different conditions to create samples with varying surface morphologies. The optical features of these samples are then analyzed using backscattering measurements and polarimetry analysis.
2:Sample Selection and Data Sources
Type 316L stainless steel sheets (1 mm thick) were selected as the original raw samples. They were prepared by wet grounding with SiC papers, cleaned ultrasonically in acetone, and rinsed in De-Ionized Water (DIW).
3:List of Experimental Equipment and Materials
Ti-Sapphire Chirped Pulse Amplified (CPA) femtosecond laser system, three-dimensional computer-controlled positioning system, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), He-Ne laser beam, half wave plate (HWP), non-polarizing beam splitter (BS), analyzer, collecting lens, black and white CCD camera.
4:Experimental Procedures and Operational Workflow
Samples were irradiated at different laser fluences and scan speeds to create varying surface morphologies. The backscattered light intensity was measured for different incident angles and polarizations. Polarimetry analysis was conducted to extract Mueller matrix elements and calculate polarimetry parameters.
5:Data Analysis Methods
The Mueller matrix elements were normalized to M00, and polarimetry parameters (diattenuation, depolarization, and retardancy) were calculated using the Lu-Chipman method. The backscattered light intensity was analyzed using an image processing algorithm and MATLAB software.
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