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Based on the lens of spatial filter parallel auxiliary assembly and collimation method, aiming at the unloading and locking problem of the filter lens after collimating, a lens parallel adjustable axial locking structure was proposed. A special elastic chuck structure was designed to realize clamping axial friction locking; each branch realized interference fit, and the adjustable structure of “line-line-line” contact realized equivalent fixation through spring pre-tightening. Compared with radial locking, the abrupt error of the axial locking lens in the unloading process of a collimating auxiliary machine was small, and the posture state maintenance and structural response stability were strong. The established homogeneous transformation matrix (HTM) and lens global error showed that the pose torsion roll error of the radial locking structure was significantly suppressed. The relative stability experiment showed that the angular drift error of the lens axial locking structure was ± 0.2 µrad. The design effectively improved the unloading anti-mutation characteristics and stability of the filter lens, which provided an experimental basis for the application of intelligent collimation assisted assembly and adjustment scheme in the upgrading of a high-power laser device.

Cleanliness management is essential for the safe operation of high power laser systems. In order to maintain the transmittance and minimize the optics damage, we should protect the optics surface with coatings from contamination. Large aperture optics in the vacuum is easily contaminated by airborne molecular from material outgas. In this paper, we introduce the techniques of cleanliness management in SG-II-UP laser facility. The online monitoring of surface airborne molecular contaminant is carried out with quartz crystal microbalance. We investigated the influence of the airborne molecular contaminant on the 351nm transmittance of fused silica optics with sol-gel coatings.

We experimentally investigated the laser damage growth behavior of multilayer dielectric gratings (MLDGs) by the picosecond pulses at 1053nm. The damage growth threshold of 2.43J/cm2 is significantly lower than the 20/1 damage threshold of 3.06 J/cm2. Once the damage site is initiated, the damage area grows linearly with shot number and saturates after sufficient shots due to the Gaussian spot. The barycenter of the growing damage site deviates from the laser spot center and their distance increases with the shot number, which indicates the asymmetry of the damage growth along the laser propagation axis. The growth rate of the damage site along the laser propagation direction is larger than that in the reverse direction by a factor of ~1.8 for various fluences. The comparison of the experimental and numerical results reveals that the asymmetrical intensity modulation induced by the damage sites causes the asymmetry in growth. The revealed characteristics and mechanisms of the damage growth can be of great significance to predict the lifetime of the MLDGs in high-power laser systems.

Many literatures have focused on the design, fabrication and intrinsic damage of multilayer dielectric gratings (MLDGs). However, contamination may be a key factor of the MLDGs lifetime. In this paper, we compare the laser damages of the clean and contaminated MLDGs, and damage threshold of clean MLDGs is 3.12J/cm2 . We obtain the curve of the critical particle size at various laser fluences, above which the MLDGs will be damaged. Intrinsic LIDT of clean MLDGs is larger than that of contaminated ones, so the cleanness control is a crucial problem for the MLDGs. The scanning electron microscope (SEM) morphologies of intrinsic and contaminant induced damages are different. The intrinsic damage is cold ablation, while contaminant induced damage is thermal ablation.

We propose two efficient methods of determining damage growth threshold (DGT) based on the saturation damage size analysis (SDSA) for multilayer dielectric gratings by picosecond pulsed lasers. The damage size at laser fluences above DGT increases with the shot number and finally saturates due to the Gaussian focal spot. The DGT is extracted by mapping the boundary of a saturation damage site obtained at single fluence to the beam profile, which is called the monofluence SDSA method. Meanwhile, the saturation damage size decreases when reducing laser fluence. The fitting and extrapolation of the saturation damage sizes at different fluences are also useful to accurately determine the DGT, which is called the multifluence SDSA method. Although the saturation damage site is asymmetric, the DGTs measured with two SDSA methods are almost identical for the same axis, and both are in very good agreement with those obtained with the growth probability method. The underlying mechanisms and advantages of two SDSA methods are extensively discussed. The consistence of two SDSA methods in determining DGT is attributed to the same morphology of the initial damage and the saturation damage boundary, as well as the local damage dynamics. The relation of the lifetime damage threshold and DGT obtained with the SDSA method is also revealed.

Strictly controlling the cleanness of transport mirror surface in high power laser system has an important significance. Removal efficiencies of dust in different sizes and on different positions of the transport mirror surface are studied, by using the air knife blowing method with different inlet pressures and installation positions. Full experiments and range analysis show that the air knife blowing method is an effective way to control the cleanness of the transport mirror surface. The removal efficiency of dust particles in different sizes and positions of the transport mirror surface is better when inlet pressure is 0.9 MPa and the air knife installation position is 3 mm. Besides that, some simulations on flow fields are conducted. The simulation results and the experimental results have a good consistency.

In high-power laser systems (HPLSs), understanding debris-removal trajectories is important in eliminating debris from the surfaces of transport mirrors online and keeping other optical components free from contamination. NS equations, the RNG $k{-}{\it\varepsilon}$ model and the discrete phase model of the Euler–Lagrange method are used to conduct numerical simulations on the trajectories of contaminant particles of different sizes and types on the mirror surface using Fluent commercial software. A useful device is fabricated based on the simulation results. This device can capture and collect debris from the mirror surface online. Consequently, the effect of debris contamination on other optical components is avoided, cleaning time is shortened, and ultimately, the cleanliness of the mirrors in HPLSs is ensured.

Component is to have a solution to reuse software and the introduction of its attempt to a low self-up, pre-and large-scale custom-assembled to resolve the problem created the software system. On the market today there are a number of components-implemented model which have been widespread used. However, due to commercial secrets, companies or organizations are reluctant to develop a component model to integrate complete programs, which make it difficulty to carry out cross-component model interoperability. In this paper, a new component model is proposed based on the Web Service technology and the strong Assembly and Disassembly of components. By separating the component-based applications with the framework of the internal components, the proposed component model is reusable and consistent to multi-platforms. The analysis of relationship between the system framework and the component model proves that component management and mutual operations are implemented inside the system framework, and the systems based on the component model are open, flexible and maintainable.