Nanostructured surfaces 

Laser-plasma structuring of glass surface with powder
Mocharskyi V.S., Kovalyuk B.P., Sitkar O.A.
Department of Physics, Ternopil Ivan Puluj National Technical University. 
Ruska Street, 56, Ternopil-46001, Ukraine. 
E-mail: vitaliimocharskyi@gmail.com

There are many ways of laser surface structuring, as well as the causing of powder materials films using laser irradiation. This paper proposes a new method of causing powder materials on the surface of the glass substrate using a specially designed method and device (Fig. 1). 

Fig. 1. Scheme of the device for laser-plasma structuring of glass surface with powder
It should be noted that this method of causing allows to adjust the resulting structures, both by changing the type of topper transparent plate and its thickness, as well as changing the clamping force between two transparent plates, and not just adjusting the power of laser radiation.
As substrates for structuring were used disks of glass K8, treatment was carried out using powders of titanium and aluminum, which had the shape of squama and dimensions: length 0.14-0.7 mm, width - 0.042-0.14 mm. Irradiation was performed with neodymium laser in the Q-switched mode, laser spot  diameter - 4 mm, energy in the pulse –  4-4.5 J, pulse duration – 50 ns. 
The performed scanning electron microscopy showed that the structure of melted and then frozened powder is formed on the surface. It should be noted that not all powder particles are completely melted. Also cracks can be seen on the surface of the substrate, which are caused by ultra-rapid expansion of the formed plasma. This method showed the possibility of creating structures from powders on the surface of two glass plates (topper and bottom).