The laser damage resistance of an optical element in high power systems depends significantly on the surface quality substrate. In this experiment, commercially polished fused silica substrates were etched argon plasma generated by a RF source and their roughness, flatness properties investigated. This method can be applied vacuum chamber prior to deposition multilayer coatings without breaking vacuum. It was shown that etching 355 nm, radiation could improved more than 8 times. However, it...

Various investigations show that damage threshold of optical coatings by intense ultrashort laser pulses is closely related to the intensity electric field at layer interfaces. LIDT measurements high reflectance using femtosecond 800 nm wavelength are presented. ZrO₂, HfO₂ and Ta₂O₅ as refractive index materials for two sets experiments were chosen. Two different coating designs investigated: standard quarter-wavelength design with SiO₂...

The nonlinear lBO (liB 3 O 5 ) crystal is widely used in many Nd : YAG, Yb KGW and YlF lasers order to generate higher optical harmonics.However, the most limiting factor such applications resistance of their coated surfaces described by so-called laser Induced Damage Threshold (lIDT) parameter.In this work we investigate "fatigue" (multi-pulse) behaviour lIDTs crystals with different types (single AR@355 nm triple AR@355+532+1064 wavelength) anti-reflective coatings while optimising...

Band-gap and refractive index are known as fundamental properties determining intrinsic optical resistance of multilayer dielectric coatings. By considering this fact we propose novel approach to manufacturing interference thin films, based on artificial nano-structures modulated porosity embedded in high band-gap matrix. Next generation all-silica mirrors were prepared by GLancing Angle Deposition (GLAD) using electron beam evaporation. High reflectivity (HR) was achieved tailoring the...

The stability of thin film coatings for applications especially in the UV spectral range is oftentimes a limiting factor further development radiation sources and beam delivery systems. Particularly, functional on laser conversions crystals as well resonator mirrors show an insufficient lifetime due to laser-induced degradation. Previous investigations power handling capability mostly concentrate properties pure oxide materials particle mitigation. Recent innovations ion sputtering...

Commercially polished fused silica substrates were etched and their optical-physical properties investigated. Resistance to laser radiation was significantly enhanced no degradation of surface roughness, flatness or loss in transmission spectra observed.

High power laser systems are one of the most rapidly growing areas in development technology. This also leads towards higher requirements for environmental stability optical components and their resistance to laser radiation. There some reports showing that porous dielectric coatings more resistant intense radiation, however they have smaller than denser coatings, which sensitive radiation. The influence important technological parameters (deposition rate, substrate temperature, energy...

The ion assisted thin film deposition (IAD) method has been used extensively for more than two decades, but questions about possibility of improving the laser-induced damage threshold (LIDT) by this compared with conventional electron-beam evaporation (non-IAD) are still not fully answered. A complete understanding different factors that can influence is necessary continued development multilayer dielectric coatings optimized high-power laser applications. To clarify these we performed...

The high-quality surface of an optical element is a prerequisite for high-power laser system design. Yttrium aluminum garnet (YAG) crystal one the most important materials solid-state active medium. Laser-induced damage threshold (LIDT) YAG crystals might substantially limit maximum output power whole system. In this research, we show novel possibility significant LIDT enhancement via plasma etching picosecond pulse durations. dependence on depth was investigated. With optimized conditions,...

Single HfO₂ layers were deposited on fused silica substrates using Hf as a starting material by PIAD technology. Inductively coupled RF plasma source was used, generating pure oxygen, well argon-oxygen mixture plasma. Mean ion energies varied from ~120 to ~270 eV. Optical properties, stress values, direct absorption for 1064 nm, surface roughness, film structure determined the samples and also compared e-beam IBS formed single layers. It is shown, that selecting proper parameters...

A comparison of laser induced damage thresholds (LIDT) ion assisted deposition (IAD) and standard electron beam dielectric coatings on BK7 glass with different surface roughness was performed. Five types high reflectance mirrors at 800 nm two 1064 were tested. Mirror made ZrO₂ SiO₂. Automated LIDT measurements performed according to the requirements current ISO 11254-2 standard. Two lasers used for measurements: Nd:YAG (l = nm, t 13 ns) Ti:Sapphire 130 fs ). All 1-kHz...

High surface quality of the optical elements is one key factors enabling their effective application in high power laser systems. In our work, commercially polished undoped YAG crystals were etched using low energy oxygen plasma. Surface roughness and properties investigated two different etching depths. Obtained results demonstrate smoothing initial crystal 1-4 % decrease transmittance within UV-VIS spectral range.

A quest for higher laser powers is one of the main driving forces in development technology. Unfortunately all components have some limit to intensity optical radiation that can be applied on them - so-called laser-induced damage threshold (LIDT). To enable further power scaling devices, novel highly resistant developed. Such are crystals, mirrors, fibers and other typically coated with periodic dielectric layers made using e-beam, sputtering or sol-gel technologies. The production materials...

The performance of optical coatings for UV region (200-300 nm) is closely related to their losses. There are a few factors which significantly influence the extinction deposited coating - deposition vacuum, contamination from filaments e-beam guns, ion source and finally, properties selected materials. In this work contribution these different was investigated evaluated. HfO₂, Al₂O₃ SiO₂ most widely used materials producing down 200 nm. Influence...

An influence of substrate temperature and working gas in coating plant during evaporation process on the laser-induced damage threshold (LIDT) high reflection dielectric coatings was experimentally investigated. Also a LIDT comparison ion assisted deposition (IAD) conventional electron-beam (non-IAD) fabricated under same (300 °C) performed. A set different type mirrors were tested for at 532 nm 3.4 ns pulses: one non-IAD six types IAD evaporated temperatures gases. All made BK7 glass...

High density, improved adhesion and environmental stability are the main features of dielectric optical coatings produced using ion-assisted deposition (IAD) technology. However, investigations resistance IAD to intensive laser radiation show controversial results. A series experiments were done examine influence ion gun operation on transmittance fused silica substrates. It was shown that source introduced extinction in UV spectral range. Optical properties single hafnia layers multilayer...

Co2+:MgAl2O4 crystals are successfully used as passive Q-switches within the cavity of erbium glass lasers. Their limited resistance to laser radiation might also put constraints on generated output peak power. Usually, polishing optical substrates induces a contaminated Beilby layer and damages subsurface layer, which leads considerably lower obtained surface. Low-energy oxygen plasma etching using different depths 50, 100, 250 400 nm was performed polished crystals. The surface morphology...

Laser induced damage of optical coatings has been one the most important targets during many decades intensive research. Different techniques were used and explored with aim to increase resistance multilayer systems laser pulses. In this work, LIDT results different “base” structures made by ion beam sputtering Al₂O₃, SiO₂ their mixtures are presented, further enhancement possibilities discussed applying additional layer structure using higher bandgap...

In this paper, we performed comparison of laser-induced damage threshold (LIDT) for ion-assisted deposition (IAD) and non-IAD coatings in nanosecond femtosecond pulse ranges. S-on-I tests were 10/sup 4/ pulses at 1-kHz repetition rate. Equivalent BK7 substrates with the same surface roughness coated two coating. The results analysed using AFM XRD. difference LIDT values 130 fs between IAD optical coating deposited on substrate polishing quality was equal within range measurement accuracy....

This investigation was aimed at optimization of optical properties, stability and radiation resistance coatings deposited using the standard vacuum coating plant equipped with ion source for assisted deposition. There are some reports showing that porous dielectric more resistant to intense laser radiation, however they have smaller environmental than denser coatings, which sensitive radiation. The influence important technological parameters (deposition rate, substrate temperature, energy...