Since the invention of femtosecond lasers, development of new laser processes never stopped to raise interest with different applications, notably in industrial sector. ALPhANOV concentrates its efforts since its creation to master and optimize these processes. Among its most recent development, nanotexturation by femtosecond laser have a prosperous future in a large range of applications.
Applied at the surface of different materials (e.g. metal or silicon) with particular parameters, femtosecond pulses enable a texturation with nanometer dimensions. Along the line of the focus spot, the matter self-arranges in a wavy structure consisting of humps and valleys called “ripples”. Period and orientation of these ripples can be controlled by the wavelength and the polarization of the light.
These structures have found a first application in a field of decoration. When the period obtained between ripples is in the same range as the wavelength of the visible light, a diffraction of the light leads to coloring effects. In particular used in luxury industry as watch making industry or fragrance, this process allow to create a real added value to the product.
At the inverse of a diffractive effect, another nanostructure can be obtained with the same optical setup called “spikes” capturing all incidents light without any reflexion. This spike structures provide a very characteristic matt black effect. Besides the esthetic aspect, this process is particularly used in photovoltaics to improve the yield of the solar cells by absorption of the light.
The same structures allow modifying the wetting properties of the surface. In this way, with the right selection of laser parameters, it’s possible to obtain a super hydrophobic surface or the opposite: a super hydrophilic surface. The high flexibility can be appreciated to modify tribologic properties of technical materials.
As other laser-based processes, nanotexturation by laser offers many advantages. In addition to being non-contact, it is a one-step process, removing time-consuming pre- and post-treatment and the need for chemicals. With a speed of few second per square centimeter, this process begins to catch interest for industrial applications.