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The laser-induced damage threshold (LIDT) is a key measure of an optical component’s resistance to laser damage, making its accurate determination crucial. Following the ISO 21254 standards, we studied the measurement strategy and uncertainty fitting method for laser damage, establishing a calculation model for uncertainty. Research indicates that precise LIDT measurement can be achieved by using a small energy level difference and conducting multiple measurements. The LIDT values for the cylindrical grating are 15.34 ± 0.00052 J/cm2 (95% confidence) and 15.34 ± 0.00078 J/cm2 (99% confidence), demonstrating low uncertainty and reliable results. This strategy effectively measures the LIDT and uncertainty of various grating surface shapes, offering reliable data for assessing their anti-laser-damage performance.

Laser processing of diamond has become an important technique for fabricating next generation microelectronic and quantum devices. However, the realization of low taper, high aspect ratio structures in diamond remains a challenge. We demonstrate the effects of pulse energy, pulse number and irradiation profile on the achievable aspect ratio with 532 nm nanosecond laser machining. Strong and gentle ablation regimes were observed using percussion hole drilling of type Ib HPHT diamond. Under percussion hole drilling a maximum aspect ratio of 22:1 was achieved with 10,000 pulses. To reach aspect ratios on average 40:1 and up to 66:1, rotary assisted drilling was employed using > 2 M pulse accumulations. We additionally demonstrate methods of obtaining 0.1° taper angles via ramped pulse energy machining in 10:1 aspect ratio tubes. Finally, effects of laser induced damage are studied using confocal Raman spectroscopy with observation of up to 36% increase in tensile strain following strong laser irradiation. However, we report that upon application of 600 °C heat treatment, induced strain is reduced by up to ~ 50% with considerable homogenization of observed strain.

Calcium fluoride (CaF2) crystals are widely utilized in deep-ultraviolet (DUV) lithography due to their excellent optical properties. The laser-induced degradation and damage of CaF2 crystals is a critical concern that restricts its extended application. Impurities of CaF2 crystal are considered a key factor affecting its laser resistance. Establishing the quantitative relationship and mechanism of impurity content impacting the degradation and damage characteristics of CaF2 crystal is essential. This study investigated the characteristics of different impurity contents affecting the degradation and laser-induced damage thresholds (LIDTs) of CaF2 crystals under X-ray and 193 nm pulsed laser irradiations, and quantitatively analyzed the degradation process and mechanism. Our findings demonstrate that impurities at ppm levels significantly diminish the transmittance of CaF2 crystals across various wavelengths following X-ray irradiation. In contrast, these impurities have a negligible effect on the LIDT test results, suggesting distinct damage mechanisms between X-ray and laser irradiation. This study provides valuable insights for optimizing the CaF2 crystal fabrication process and enhancing irradiation resistance.

Nanoscale laser damage precursors generated from fabrication have emerged as a new bottleneck that limits the laser damage resistance improvement of fused silica optics. In this paper, ion beam etching (IBE) technology is performed to investigate the evolutions of some nanoscale damage precursors (such as contamination and chemical structural defects) in different ion beam etched depths. Surface material structure analyses and laser damage resistance measurements are conducted. The results reveal that IBE has an evident cleaning effect on surfaces. Impurity contamination beneath the polishing redeposition layer can be mitigated through IBE. Chemical structural defects can be significantly reduced, and surface densification is weakened after IBE without damaging the precision of the fused silica surface. The photothermal absorption on the fused silica surface can be decreased by 41.2%, and the laser-induced damage threshold can be raised by 15.2% after IBE at 250 nm. This work serves as an important reference for characterizing nanoscale damage precursors and using IBE technology to increase the laser damage resistance of fused silica optics.

A transparent nonlinear optical (NLO) organic single crystal of l-threoninium p-toluenesulfonate (LTPTM) monohydrate was obtained using the slow evaporation solution growth technique over a span of 5 weeks. It crystallizes in the non-centrosymmetric space group P21, which is the same as that described in the literature. Photoluminescence spectroscopy was used to assess its optical characteristics. Hirshfeld surface analysis of LTPTM and its donor and acceptor sites was carried out using CrystalExplorer software. The mechanical stability of the titled material was assessed by applying shock waves to determine its optical, structural, and morphological properties after shock. In addition, the nanoindentation technique was used to investigate the mechanical stability at the nanoscale, and several characteristics including stiffness, Young’s modulus, and hardness were also calculated. The laser damage threshold determined its capacity to withstand intense laser radiation. The dielectric properties were also analysed. All these studies revealed the potential for application of LTPTM in various NLO and optoelectronic devices.

We present a fully three-dimensional kinetic framework for modeling intense short pulse lasers interacting with dielectric materials. Our work modifies the open-source particle-in-cell code EPOCH to include new models for photoionization and dielectric optical response. We use this framework to model the laser-induced damage of dielectric materials by few-cycle laser pulses. The framework is benchmarked against experimental results for bulk silica targets and then applied to model multi-layer dielectric mirrors with a sequence of simulations with varying laser fluence. This allows us to better understand the laser damage process by providing new insight into energy absorption, excited particle dynamics and nonthermal excited particle distributions. We compare common damage threshold metrics based on the energy density and excited electron density.

Single crystal of Piperazinium citrate (PC) was grown from aqueous solution by slow evaporation solution growth method. Single crystal X-ray diffraction study (SXRD) reveals that the grown crystal belongs to monoclinic system with the space group Pn. The crystalline nature of PC crystal was analyzed by Powder XRD method. The crystal morphology and growth axis of Piperazinium crystal were investigated. The crystal's various functional band frequencies were confirmed through FTIR and FT-Raman spectroscopy analyses. In order to determine the optical transparency, cutoff wavelength, and band gap energy of PC crystal, a UV–Visible spectral study was carried out. The results indicated that the crystal was transparent throughout the entire visible-NIR spectrum. Sharp emission peaks can be seen in the photoluminescence spectrum, indicating ultraviolet (UV) emission. Laser induced damage threshold study was carried out using Nd:YAG laser at operating frequency of 1064 nm. Third-order nonlinear optical properties such as nonlinear refractive index, nonlinear absorption coefficient, and third-order nonlinear susceptibility of the grown PC crystal were calculated by Z-Scan technique.

The laser-induced damage threshold (LIDT) of plate laser beam splitter (PLBS) coatings is closely related to the subsurface absorption defects of the substrate. Herein, a two-step deposition temperature method is proposed to understand the effect of substrate subsurface impurity defects on the LIDT of PLBS coatings. Firstly, BK7 substrates are heat-treated at three different temperatures. The surface morphology and subsurface impurity defect distribution of the substrate before and after the heat treatment are compared. Then, a PLBS coating consisting of alternating HfO2–Al2O3 mixture and SiO2 layers is designed to achieve a beam-splitting ratio (transmittance to reflectance, s-polarized light) of approximately 50:50 at 1053 nm and an angle of incidence of 45°, and it is prepared under four different deposition processes. The experimental and simulation results show that the subsurface impurity defects of the substrate migrate to the surface and accumulate on the surface during the heat treatment, and become absorption defect sources or nodule defect seeds in the coating, reducing the LIDT of the coating. The higher the heat treatment temperature, the more evident the migration and accumulation of impurity defects. A lower deposition temperature (at which the coating can be fully oxidized) helps to improve the LIDT of the PLBS coating. When the deposition temperature is 140°C, the LIDT (s-polarized light, wavelength: 1064 nm, pulse width: 9 ns, incident angle: 45°) of the PLBS coating is 26.2 J/cm2, which is approximately 6.7 times that of the PLBS coating deposited at 200°C. We believe that the investigation into the laser damage mechanism of PLBS coatings will help to improve the LIDT of coatings with partial or high transmittance at laser wavelengths.

In this work, we have grown an organic nonlinear crystal of 4-methylpyridinium 2, 4-dinitrophenolate with reasonable size by slow evaporation solution growth method using ethanol solvent at ambient temperature. A well-developed surface crystal was selected for characterization studies, and single-crystal X-ray diffraction analysis provided a centrosymmetric monoclinic crystal structure. Various functional groups and different vibrational modes were identified using Fourier transform-infrared spectroscopy studies. Fluorescence emission declares that 4MPDNP crystal serves as a photoactive material. The optical transparency and optical band gap energy were examined by the UV–visible spectrum. Thermogravimetric and differential scanning calorimetry analyses were employed to understand the thermal and physio-chemical stability of the title compound. The relative dielectric permittivity and laser damage threshold of the grown crystal were measured by LCR/impedance analyzer and Q-switched Nd: YAG laser, respectively. The magnitude of third-order nonlinear optical parameters was evaluated by the Z-scan technique.

An attack on devices with laser damage to optical components referred to as “laser-damage attack” in the literature can allow an intruder to reduce the attenuation of optical elements and lead to the distributed key compromise. A method for protection against this attack using a device with a collapsing mirror is discussed. The efficiency of the protection method proposed has been confirmed by the experimental data.