Non-symmetric and directional reflectivity from three dimensional (3D) laser induced periodic surface structures (LIPSS) is considered. LIPSS structures were patterned in stainless steel (W720) by using linear and elliptical polarized laser beams from a femtosecond (fs) laser. The short and long periodic ripples and possible other type artifact remaining has decreasing influences to relative reflectivity variation between 5% and 65% in the wavelength range from 200nm to 800nm. The studies of patterned W720LIPSS structures indicated, besides of increased surface area, that decrease of reflectivity is affected by light scattering from ultra-structures of LIPSS and produces resonance type differences in spectral reflectivity when either TM or TE polarized probing beam interacts with micro- and ultrastructure of LIPSS.
Chemical components and initial optical responses of Ti35Nb6Ta alloy are reported. Polished titanium and other titanium
alloy Ti6Al4V served as reference surfaces. The chemical composition was determined with an X-ray photoelectron
spectroscope (XPS) for the surfaces as well as for water, phosphate buffered saline (PBS) and for human plasma
fibrinogen (HPF in PBS) exposed surfaces. The reflectance of the surfaces was modeled utilizing Bruggeman's model, to
evaluate the optical changes that the chemical reaction of each liquid can produce. After the model, a diffractive optical
element (DOE) based sensor was used to determine the temporal optical signal from the sample surfaces. The coherent
and non-coherent signals gathered with DOE sensor were compared to the reflectance model. Exposing to the liquids
showed surface oxidation, which could produce lowered reflectance of the surface. The model and the initial temporal
responses showed similarities in non-coherent reflectance.
Optical properties of different type of surface treatments of titanium biomaterial as polishing, grinding, and chemical etching are investigated in details. The main aim of this study is in sensing the organisation of nano-scale fibrinogen and oligonugleotides adhered on biomaterial surface. Thus permittivity change and the fluctuation in optical roughness of treated titanium surface, when titanium surface is subjected to the contamination of buffer fractions as well as to the contamination of human plasma fibrinogen fraction, are investigated through optical window of a cuvette by using diffractive optical element based sensor. During the progress of this work also optical ellipsometry as a corroborative method was used to verify the attachment of the molecules on the biomaterial surface.