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A principal possibility to overcome fundamental (intrinsic) limit of pure optical materials laser light resistance is investigated by designing artificial materials with desired optical properties. We explore the suitability of high band-gap ultra-low refractive index material (n less than 1.38 at 550 nm) in the context of highly reflective coatings with enhanced optical resistance. The new generation all-silica (porous/nonporous) SiO2 thin film mirror with 99% reflectivity was prepared by glancing angle deposition (GLAD). Its damage performance was directly compared with state of the art hafnia/silica coating produced by Ion-Beam-Sputtering. Laser-Induced Damage Thresholds (LIDT) of both coatings were measured in nanosecond regime at 355 nm wavelength. Novel approach indicates the potential for coating to withstand laser fluence of at least 65 J/cm2 without reaching intrinsic threshold value. Reported concept can be expanded to virtually any design thus opening a new way of next generation thin film production well suited for high power laser applications.

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Waveplates, used to modify polarization state of light, are integral part of high‐power lasers. Classical approach to waveplate manufacturing is based on combination of birefringent crystalline materials and deposition of nonpolarizing antireflection (AR) coatings. Their limitation to withstand maximal peak power is determined by laser‐induced damage (LID) phenomena, mainly determined by low band‐gap materials used in AR coatings. In this study, a novel multi‐layer approach of high band‐gap birefringent coatings was proposed and investigated to overcome this limitation. Three eligible candidate materials, namely LaF3, Al2O3, and SiO2 are investigated. Structural and optical analysis reveal superior properties of silica for UV spectral range. Zero‐order thin film retarders based on all‐silica nano‐structures are fabricated by oblique angle deposition process. Low optical losses and high transparency (T ∼ 99%) are demonstrated while indicating potential to withstand high laser fluence of 40 J cm−2 in nanosecond regime at 355 nm wavelength. Such waveplates can essentially improve maximal tolerated peak power and thus allow production of more compact optical systems, even when high laser power is used.

The nonlinear lBO (liB 3 O 5 ) crystal is widely used in many Nd : YAG, Yb : KGW and Nd : YlF lasers in order to generate higher optical harmonics. However, the most limiting factor in such applications is the optical resistance of their coated surfaces described by the so-called laser Induced Damage Threshold (lIDT) parameter. In this work we investigate the "fatigue" (multi-pulse) behaviour of lIDTs in lBO crystals coated with different types of (single AR@355 nm and triple AR@355+532+1064 nm wavelength) anti-reflective coatings while optimising the refractive index designs and selecting appropriate sub-layer materials. All the coatings were produced of different oxide materials (ZrO 2 , Al 2 O 3 , SiO 2 ) and ZrO 2 -SiO 2 mixtures by using the ion beam sputtering (IBS) deposition technique. The optical damage resistance of both fixed and transient refractive index coatings is of special interest. Besides the spectral properties, the resistance to laser irradiation is characterised at the wavelength of 355 nm with laser pulses of nanosecond duration. The conclusions are drawn about the AR coated lBO with the most successful designs by the means of optical resistance.