In order to obtain more information of far-field beam profile from limited measured data, a novel super-resolution reconstruction method for far-field beam profile based on deep learning is proposed. In this paper, the high/low resolution spot image sample is obtained by simulation, the EDSR neural network training model is used to study the mapping relationship between high/ low resolution spot images, and the super-resolution reconstruction method based on deep learning is realized. The experimental results show that the super-resolution reconstruction based on deep learning is superior to the conventional algorithms in PSNR and SSIM.
A new scheme for Stimulated Brillouin Scattering (SBS) suppression is proposed based on multi-point pump technique. The pump power is coupled into the double-clad fiber by several pump points instead of one fiber combiner, which will rearrange the pump power distribution along the active fiber and influence the amplifier process of SBS light. The numerical simulation indicates that SBS is effectively suppressed in a fiber amplifier with an output up to 700W and a 1kHz line-width by virtue of the configuration. Besides, the SBS threshold demonstrates a 3.7 times increase compared with an strain allied scheme.
For the high power laser system, the power of laser to the target, the power of the bucket and the beam quality are important parameters, which have important value of identification and evaluation. However, the power density of high power laser are too high to affect the test system. And the high precision attenuation method of Fresnel reflection method can effectively solve this problem. The laser incidents on Front surface of uncoated dielectric material at near normal products different reflectivity of components in s-direction and p-direction. The effect of the difference of reflectivity can be effectively solved by placing a pair of wedge off the axis and changing the polarization state of the reflected light, the reflectivity of the S-direction is as same as p-direction components at every two stages by two normal vertical reflectors. The accurate reflectivity can be obtained according to the refractive index coefficient of dielectric materials. Under the condition of low-power near-infrared power incident light, the calculated results are consistent with the measured results. And under the condition of high power density, we study the thermal deformation of fused silica mirror. A mirror thermodynamics model based on the software was built. And experimental measurements for thermal deformation were performed with laser intensity as high as 44 kW/cm2. The thermal deformation mainly depends on the absorption of the film layer. Therefore, shape variables can be significantly reduced by using a non-coated lens or reducing the absorption of the film.
In this paper, we designed an optical attenuator based on optical scatting. Which consist of an optical scatting material and cylindrical attenuation structure. The diffusing characteristics of material and attenuation properties of the device have been simulated by ray-tracing, and the simulated results agree very well with the experimental results. The attenuator has been successfully used in high energy laser beam intensity profile measurement system.
In this paper, an analytic model of beam profile error evaluation for detector array method is advanced. The model based on Gaussian beam distribution considering spatial sampling frequency, the non-uniformity of detectors and the high frequency components of integral laser spot. Finally, the analytic error model of laser beam profile evaluation was obtained by derivation and calculation. The model is adapted to calculate the integral energy, the beam centroid, and beam size of Gaussian approximation beam and can be extended to monotonous distribution beam.
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