Study of the near-field modulation property of microwaviness on a KH2PO4 crystal surface
Study of the near-field modulation property of microwaviness on a KH2PO4 crystal surface
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DOI：
10.1088/1674-1056/19/6/064203
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发表时间：
2010
影响因子：
1.7
通讯作者：
Chen Ming-Jun;Jiang Wei;Li Ming-Quan;Chen Kuan-Neng
中科院分区：
文献类型：
--
作者：
Chen Ming-Jun;Jiang Wei;Li Ming-Quan;Chen Kuan-Neng
KH2PO4晶体是光学惯性约束聚变（ICF）系统的关键部件。KH2PO4晶体表面的微波度与其损伤阈值密切相关，损伤阈值是其应用的关键参数。为了研究微波致激光损伤机理，本文用傅里叶模态方法讨论了微波对入射波的近场调制特性。研究结果表明，加工表面的微波特性会使入射波发生畸变，从而导致晶体内部光强分布不均匀；在普通微波幅值范围内，每增加10 nm，光强调制度增加约0.03；一级衍射效率是晶体内部光强调制的关键因素；当微波周期小于0.712 μm时，光强调制仅以倏逝波的形式存在于微波周围，而不在晶体内部；光强调制度在1.064 μm和1.6 μm微波周期有两个极值点，在3 μm到150 μm微波周期内保持不变，在150 μm以上到920 μm微波周期内逐渐下降。
The KH2PO4 crystal is a key component in optical systems of inertial confinement fusion (ICF). The microwaviness on a KH2PO4 crystal surface is strongly related to its damage threshold which is a key parameter for application. To study the laser induced damage mechanism caused by microwaviness, in this paper the near-field modulation properties of microwaviness to the incident wave are discussed by the Fourier modal method. Research results indicate that the microwaviness on the machined surface will distort the incident wave and thus lead to non-uniform distribution of the light intensity inside the crystal; in a common range of microwaviness amplitude, the light intensity modulation degree increases about 0.03 whenever the microwaviness amplitude increases 10 nm; 1 order diffraction efficiencies are the key factors responsible for light intensity modulation inside the crystal; the light intensity modulation is just around the microwaviness in the form of an evanescent wave, not inside the crystal when the microwaviness period is below 0.712 μm; light intensity modulation degree has two extreme points in microwaviness periods of 1.064 μm and 1.6 μm, remains unchanged between periods of 3 μm and 150 μm, and descends above the period of 150 μm to 920 μm.