In this study, a cadmium sulfide (CdS) line with a diameter of 204 nm and a length of 15 μm was used as the core design of the optical cavity (Fig. 1). The high refractive index of the nanowires causes the incident light to have a high reflectivity factor at the end face and be guided by the nanowires. This arrangement forms the Fabry-Burrow cavity, which, when activated by an external light source, forms a laser. The laser wavelength thus formed depends on the refractive index around it. By measuring the wavelength of the most powerful laser output, the refractive index of the liquid immersed in the nanowires can be determined.
There are a variety of methods for surface nanocrystallization of materials. There are a large number of surface nanocrystallization technologies. It is a surface layer which can realize the nano-characteristics by means of laser surface treatment technology and nanometer technology. It can be collectively referred to as laser surface nanocrystallization technology; More generally referred to as laser nano-surface engineering technology, is directly or mainly the use of laser this specific technical means to directly change or add material to change the surface of the solid material is treated, the composition or structure, so that the formation of nano-crystal Grain or a certain nanoparticle composition of the surface layer. Or the use of laser etching, laser embossing, laser hair, laser micro-nano modeling and other means to achieve nano-structure on the surface of the material.
In the 1970s, after the successful development of high-power lasers, blue laser pointer surface treatment technology into the practical application, and then the rapid development, there have been laser quenching (laser phase hardening surface modification technology), laser remelting, laser surface alloying, Laser cladding, laser surface amorphization and laser shock enhancement. These laser surface treatment technology through the surface of the material to form a certain thickness of the treatment layer to improve the mechanical properties of the material surface, metallurgical properties, physical properties, thereby enhancing the parts, the workpiece wear, corrosion resistance, fatigue and other properties. Laser due to high power density, good direction, energy transfer convenience, can be transmitted in a variety of transparent media and other characteristics.
Generally refers to the use of laser remelting, high-energy 300mw laser pointer surface melting and not add any other ingredients to the substrate surface rapid melting and solidification grain refinement, eliminate defects, reach the aim of improving the surface structure. Laser remelting as a kind of surface engineering technology, a large number of researchers have done related research work, pointed out that the research can significantly improve the surface hardness and corrosion resistance of the material and wear properties by laser remelting, but as the surface of nanometer technology is not clearly separate.