In this study, ZnS/YbF₃-10.6 µm antireflection (AR) coatings were fabricated on CVD single-crystal diamond and ZnSe substrates. The spectral characteristics of the coatings and their performance under continuous wave laser radiation at 10.6 µm were systematically investigated. The fabricated AR coatings exhibited excellent spectral properties in the target wavelength range. Both theoretical calculations and experimental results indicated that, at the same power density, the 10.6 µm AR coatings on diamond substrates exhibited a lower temperature rise compared to those deposited on ZnSe substrates. Due to its high thermal conductivity, the diamond substrate is expected to exhibit reduced thermally induced surface distortion. The laser-induced damage threshold (LIDT) test results indicate that the AR coating deposited on the ZnSe substrate exhibits a damage threshold of 11,890 W/cm², whereas the AR coating on the diamond substrate achieves a threshold of 15,287 W/cm², representing a 28.5% improvement over the ZnSe substrate. Additionally, graphite formation occurs on the diamond substrate under high power density. These findings provide both theoretical and experimental support for the potential application of diamond materials in high-power laser systems.

The design and fabrication approach of a dichroic beamsplitter to meet the protection requirements of infrared detectors for blinding laser weapons is presented. The dichroic beamsplitter must protect against 1064 and 532 nm lasers and have high transmittance in the detection beam band of 3.6–4.7 µm. In order to realize the protection and antireflection (AR) functions of the dichroic beamsplitter, Ta₂O₅, which has a wide band gap and high thermodynamic stability, was selected as the high-refractive-index material. A multilayer stack was deposited on a silicon substrate by ion-assisted electron beam evaporation. The manufactured dichroic beamsplitter features a high laser-induced damage threshold (LIDT), excellent spectral characteristics in the requested spectral region, and good environmental stability.

Hf_1−xSi_xO₂ nanocomposites with different SiO₂ doping ratios were synthesized using an ion-assisted co-evaporation process to achieve dense amorphous Hf_1−xSi_xO₂ coatings with low loss and a high laser-induced damage threshold (LIDT). The results showed that the Hf_1−xSi_xO₂ nanocomposites (x ≥ 0.20) exhibited excellent comprehensive performance with a wide band gap and a dense amorphous microstructure. High-temperature annealing was carried out to ensure better stoichiometry and lower absorption. Precipitation and regrowth of HfO₂ grains were observed from 400 °C to 600 °C during annealing of the Hf_0.80Si_0.20O₂ nanocomposites, resulting in excessive surface roughness. A phenomenological model was proposed to explain the phenomenon. The Hf_1−xSi_xO₂ nanocomposites (x = 0.3 and 0.4) maintained a dense amorphous structure with low absorption after annealing. Finally, a 1064-nm Hf_0.70Si_0.30O₂/SiO₂ high-performance reflector was prepared and achieved low optical loss (15.1 ppm) and a high LIDT (67 J/cm²).

HfO2 prepared by ion beam sputtering (IBS) is widely used as a high-refractive index material for making low-loss laser films. The challenge of a high-performance HfO2 film is to simultaneously obtain an amorphous morphology with low scattering and a stoichiometric structure with low absorption. Furthermore, nanometer-sized voids are commonly present in IBS films due to excessive oxygen and argon adsorption during deposition, which is the primary barrier to achieve a smooth surface and low optical loss of HfO2. Thin amorphous SiO2 layers were added periodically into HfO2 coatings using the IBS process to synthesize amorphous HfO2 / SiO2 nanolaminate-based composites. The resulting composites exhibited excellent comprehensive performance with a dense amorphous microstructure and a void-free smooth surface. High-temperature annealing was performed to ensure superior stoichiometry and lower absorption. However, the crystalline states and microstructure of some composites evolved during the gradual annealing. We present a detailed study of the crystallization, surface topography, and absorption evolution in HfO2 / SiO2 nanolaminates as a function of HfO2 sublayer thickness and thermal annealing temperature. Moreover, the interplay between crystallization, surface topography, and absorption is elucidated. The HfO2 / SiO2 nanolaminate with 19 thin layers maintained a dense amorphous structure with low absorption after annealing. Finally, a 1064-nm HfO2 / SiO2 nanolaminate-SiO2 high-performance reflector was prepared and achieved lower absorption with a smooth surface after annealing, which demonstrated the great potential of the HfO2 / SiO2 nanolaminates for considerably improving optical loss.

La_1-xAl_xF₃ nanocomposite coatings with various amounts of AlF₃ in LaF₃ were deposited on the fused silica substrate using double-source electron beam co-evaporation. The effects of the material composition on the chemical composition, optical properties, microstructure properties, and residual stress of these deposited coatings were investigated. The results showed that although the doping of AlF₃ led to a reduction in the refractive index, the overall performance of the nanocomposites showed remarkable improvement. The increase in the AlF₃ content of prepared nanocomposites caused a decrease in the crystallinity, surface roughness, residual stress, and optical loss. Compared to polycrystalline LaF₃, the La_1-xAl_xF₃ nanocomposite (x ≥ 0.3) retained an amorphous structure, showcasing smooth surface morphology and lower absorption. As a result, the total optical loss was reduced. Additionally, the tensile stress was also mitigated to a certain extent, which means that the nanocomposite material was less prone to cracking. Finally, a 193 nm-La_0.70Al_0.30F₃/AlF₃ high reflective coating was prepared, which achieved an improved reflectance of 98.7% and better film quality compared to the pure LaF₃/AlF₃ sample. These findings clearly indicate the significant potential of La_1-xAl_xF₃ nanocomposites for developing deep ultraviolet band thin films, extending even into the vacuum ultraviolet band.

The paper investigates the thermal effects caused by nodules in reflective coating under continuous-wave laser irradiation. Simulation calculations reveal how nodule morphology and material absorption influence thermal effects. A preliminary correlation between defects and thermal effects has been established.