| Abstract [eng] |
Current modern and innovative optical devices feature an integrated laser system when high power or precision is needed. Applications are in a variety of areas such as material processing (cutting, drilling), medicine, communications technology, etc. In order to apply laser systems more in everyday life, the system dimensions should be reduced. Thus, novel solutions are required for optical components, such as polarizers, apertures or spatial filters. In order to improve polarizing optical component a few microns thick structural thin film can be deposited directly on existing elements in the microlaser system (mirrors, nonlinear crystals, etc.). Unfortunately, standard isotropic multilayer coatings can only be used as a separate element (thin film polarizers, cube polarizers), in order to control the beam polarization, as it must be installed at specific angle (Brewster angle). Using a multilayer of anisotropic columnar structure to form a dielectric coating, we can achieve polarizing optical component for zero angle. In this work, glancing angle deposition method is used to obtain nano-structured anisotropic layers. Evaporation of amorphous materials while manipulating the orientation of the substrate during process induces the self–shadowing effect. Using physical vapor deposition method and changing the angle of a substrate, different refractive index of anisotropic layers may be achieved, thus, combining the layers which has similar refractive indexes in one direction and different in other direction, polarizer is formed. In this case, multilayer in similar refractive index direction acts like a simple singlelayer, while in other direction Bragg mirror is formed. Investigation of optical and structural properties indicates the possibility to form the all-silica polarizers for zero angle of incidence. Such optical elements exhibit high optical resistivity to laser radiation, high transmission or reflection, superior optical performance and has very low optical losses. In this work, three polarizing elements were formed, and laser induced damage threshold was measured. Sculptured thin films based polarizer resistivity to laser light value is around 9,8 J/cm2 (p polarization) and 11,2 J/cm2 (s polarization). |
