熔石英元件非吸热性杂质对后表面光场的调制

为了研究熔石英元件体内非吸热性杂质导致损伤和光束质量下降,采用时域有限差分法计算杂质散射光场和分步傅里叶算法计算散射光场非线性传输的方法,得到了半径在入射波长量级的气泡和氧化锆杂质可放大光场振幅约1.6和1.9倍,且经非线性传输光场会分裂,调制会加深的结果。结果表明,元件体内杂质可导致元件后表面的损伤和光束质量的下降。

Light intensification by non-absorbing bulk defects in fused silica optics at the rear surface

Defects such as voids and high refractive index inclusions in fused silica can initiate laser damage on rear surface and downstream optics in high-power laser. The present paper simulates the intensification due to spherical voids and zirconia inclusions on rear surface by FDTD and split Fourier arithmetic. The simulation shows the voids and zirconia inclusions of radius comparable to the wavelength would amplify the electromagnetic field amplitude by about 1.6 and 1.9. after the nonlinear transportation in the nonlinear material, the modulation would decrease but the beam field would split therefore the beam quality would deteriorate.