| Abstract [eng] |
The main aim of this dissertation was to identify physical causes that limit optical component‘s spectral properties and resistance to laser radiation as well as to optimize the final substrate preparation procedure and coating deposition technology. In this work we report an experimental investigation of subsurface damage (SSD) in conventionally polished fused silica (FS) substrates, which are widely used in laser applications and directly influence performances of optical elements. Subsurface damages are defined as residual digs and scratches, some of which are filled with polishing slurry and covered with so-called Bielby layer (polished layer). Acid etching procedure of FS substrates was developed, which allows removing polished layer and eliminating SSD. Different durations of acid etching have been used to study laser induces damage threshold (LIDT) of FS substrates. These experiments revealed that the optimal etching time is ~1 min for a given acid concentration. LIDT of etched FS samples increased ~4 times. The LIDT in LiB3O5 (LBO) crystals coated with different types of (single AR@355 nm and triple AR@355+532+1064 nm wavelength) anti-reflective coatings was also investigated. All these coatings were produced of different oxide materials (ZrO2, Al2O3, and SiO2) and ZrO2-SiO2 mixtures by using the ion beam sputtering (IBS) deposition technique. Also, we present explorations of reactive magnetron sputtering technology for deposition of ZrO2 and Nb2O5/SiO2 mixture thin films at low substrate temperature. A high deposition rate (64 % of the pure Zr metal rate) process of zirconium oxide is obtained by employing active feedback reactive gas control which creates a stable and repeatable deposition processes in the transition region. |
