Methods of reactive magnetron sputtering using the sequential oxidisation of a sputtered metal film from two magnetron sources, in a rotating substrate system, have been developed. A rotation rate of around one revolution per second enhanced atomic level mixing of the film constituents on the substrate. Depending on the materials involved, two very fast feedback methods were employed to automatically control the admission rate of oxygen into the sputtering system. These methods were plasma emission monitoring (PEM), which was used to control the reactive sputter-deposition of In, Zn, W, V, Mo and Ti oxide, and voltage control, which was used to control the reactive sputter-deposition of Zn, Cu, Pb and Al oxide. The stoichiometry of the film was controlled by PEM or voltage control on one magnetron, and dopants were added by sputtering from the other magnetron. In other words, the former magnetron served two purposes; the first was to sputter metal and oxidise it, and the second purpose was to oxidise the metal sputtered from the other magnetron.

In the last years, intensive research on new tunable solid state laser materials has been carried out. For the spectral range from 1300 to 1600 nm the Cr4+ ion seems to be the most promising laser-ion. In order to meet the the demand of broad-band devices, we employed the Cr4+ doped YAG crystal fibers with high optical quality thin films design and coating (high index material TiO2, low index material SiO2) to achieve the development of high efficiency crystal fiber lasers. In this thesis, crystal fiber was used as the laser gain medium, and coated with optical thin films at both end faces (input face 900-1100 nm AR and 1300-1600 nm HR; output face 1300-1600 nm HR) as the laser cavity to reduce the loss and promote laser efficiency. During the experiment, we tried to optimize the coating conditions to acquire high density, stable index and low absorption coefficient thin films. With different thin film thickness and stacking designs, the electric field distribution was designed to be away from the laser interface and high index region to increase the laser-induced damage threshold and lifetime for high power pumping. In addition, CaO and Cr2O3 were deposited on Cr4+:YAG source rods before the laser-heated-pedestal growth to increase CaO and Cr2O3 doping concentration for higher fluorescence efficiency and signal saturation power.

In the past three decades, Nd:YAG has been the dominating high power solid-state laser gain medium. Compared with Nd:YAG, Yb:YAG has lower quantum defects which produces less heat so that it can reduce thermo-optical deformation. In addition, the achieved doping concentration can be 100%, and the absorption FWHM at 941 nm is 18 nm. Based on above listed advantages, Yb:YAG has the potential to replace Nd:YAG. Using Yb:YAG as the laser gain medium in reentrant two-mirror laser cavity, we have succeeded in Yb:YAG ring laser and all the intracavity elements are coated by our electron gun deposition system. The main purpose of my research is to continue the previous result (slope efficiency: 20.1%), and further increasing the slope efficiency of our ring cavity with different round-trip transmittance of couplers. Besides, we measured and analyzed the polarization of the planar and non-planar ring cavities. At present, the highest slope efficiency we achieved is 38.9% with a round-trip transmittance of 16.4%.

Evaluation of the wet etching properties of several different thin film oxidesgrown by physical vapour deposition was performed in this work. MgO, Al2O3,SiO2, TiO2, HfO2 ZrO2 and Y2O3 were coated on two types of substrates; Si andborosilicate glass and etching tests were performed in different etchingsolutions. MgF2 thin films have also been evaluated. Important aspects of the choice of the thin films was taken into account in orderto match to good optical properties such as refractive index (n), extinction coefficient (k) and optical thickness (TP) as well as good chemical properties in the wet etching process. A description is made of the physics of optical filters and how a combination of different oxides stacked onto each other can create interference filters. A description of the manufacturing process of the thin films where physical vapour deposition (PVD) was used is presented. Thermal shift of the optical spectra caused by porous coatings was investigated and analyses of the thin films by ellipsometry, surface profilometry and transmission spectrophotometry have been performed. The wet etching properties were evaluated by monitoring the transmission insituon transparent borosilicate glass substrates. A method of how to measure the wet etching rate for different thin films is described. A computer software was used to calculate the Pourbaix diagrams in order to understand the chemical behaviour of the etching solutions. The pH can have a significant impact on the etching behaviour. In case of TiO2, it can be dissolved in an alkaline solution of H2O2. The catalytically process behind this is evaluated. Etching rate for both Y2O3 andSiO2 were matched by adjusting the etchant concentration as a case example. The group IVB oxides are difficult to etch. The catalytic etching of TiO2 with peroxide is slow but detectable. Al2O3, Y2O3 and MgO are reasonably easy to etch but have too low refractive indices to be useful in multilayer optical filters. The In-situ etching instrument was found to be very useful for measuring etching rates. / Utvärdering av våtkemiska egenskaper för flera olika oxidtunnfilmer utfördes idetta arbete på tunnfilmer av MgO, Al2O3, SiO2, TiO2, HfO2 ZrO2 and Y2O3 vakuumdeponerade på både kiselwafers och borosilikatglas. Etstester gjordes med ett flertal etslösningar. Även MgF2-tunnfilmer utvärderades. Både optiska och kemiska egenskaper togs i beaktande vid utvärderingen av tunnfilmerna. De optiska lagar som gäller för tunnfilmer redovisas, bl a hur kombinationer av olika oxider kan skapa interferrensfilter. En beskrivning av tillverkningsprocessen varvid PVD användes presenteras. Termiskt skift av det optiska transmissionsspektrat orsakat av porositet undersöktes. Analyser av tunnfilmerna med ellipsometri, profilometri och transmissions spektroskopi utfördes. Våtetsningsegenskaperna utvärderades genom att mäta in-situ vid etsprocessen på transparenta borosilikatglassubstrat. Metoden för att mäta etshastigheten för olika oxider är beskriven. Datorberäkningar av pourbaixdiagram användes för att skapa en förståelse av de kemiska egenskaperna för etslösningarna. Etsegenskaperna påverkas till stordel av lösningens pH. TiO2 kan etsas i basisk lösning av peroxid. Denna process utvärderades, likaså utvärderades etshasigheten för Y2O3 och SiO2 för att erhålla matchande par avoxider som en fallstudie. Grupp IVB oxiderna är mycket svåra att etsa. Katalytisk etsning av TiO2 med peroxid är detekterbar men långsam. Al2O3, Y2O3 och MgO är förhållandevis enkla att etsa men har för låga brytningsindex för att var praktiskt använbara i optiska multilagerfilter. In-situ etsinstrumentet befanns vara ett utmärkt verktyg för att mäta etshastigheten för tunnfilmer.

Interference filters are multilayer thin film devices. They use interference effects between the incident and reflected radiation waves at each layer interface to select wavelengths. The production of interference filters depend on the precise deposition of thin material layers on substrates which have suitable optical properties. In this thesis, the main target is to design and produce two optical filters (short-pass filter and long-pass filter) for the CCDs that will be used in the electronics of a space camera. By means of these filters, it is possible to take image in different bands (RGB and NIR) by identical two CCDs. The filters will be fabricated by plasma ion-assisted deposition technique.

Šiame darbe yra aptariama sklaidos matavimo sistema sukurta plačioje spektro srityje reikalingiems matavimams atlikti. Joje naudojami parametriniai šviesos generatoriai bei harmonikų generatoriai, kaupinami nanosekundinės trukmės impulsais, ir apibendrinami sklaidos tyrimai, atlikti įvairių tipų optinėse dangose ir netiesiniuose optiniuose kristaluose, naudojant derinamojo bangos ilgio lazerinius impulsus. Pirmą kartą buvo ištirti naujų netiesinėje optikoje perspektyvių LiInS2 ir LiInSe2 kristalų sklaidos nuostoliai infraraudonojoje srityje. Taip pat parodyta, kad koherentinės sklaidos tomografijos metodas, anksčiau taikytas puslaidininkinių kristalų tūriniams defektams tirti, yra tinkamas ir netiesinėje optikoje naudojamų kristalų kokybės tyrimams. / This work describes the system for the light scattering measurements in a wide spectral range, which uses the light parametric oscillators and harmonic generators pumped with a nanosecond pulses and summarizes the research in various types of coatings on optical components and inside nonlinear optical crystals. The total scattering losses for the first time were characterized in the infrared region for a new promising in nonlinear optics LiInS2 and LiInSe2 crystals. It was shown that the laser scattering tomography, previously used for investigation of volume defects in semiconductor crystals, can be applied in the nonlinear optical quality control.