摘要
焦斑的尺寸和形状主要由光束的波前畸变决定。为了减小大口径激光系统的波前畸变并提高焦斑能量集中度,对静态波前畸变采用了相位板补偿的方法。对于在建中的原型装置,主要考虑补偿主放大系统的波前畸变。根据补偿板摆放位置处的光通量和加工的难易程度,综合考察了四个摆放位置的优缺点,提出用补偿板替代腔镜对波前进行补偿。建立了求解补偿板面形的数值计算模型,就设计时采用的钕玻璃片滤波截止频率做了讨论,得出用0.01 mm-1的截止频率做低通滤波后可以得到最佳补偿效果,给出了补偿板的面形分布和加工方法。模拟结果表明,采用这种方法后静态波前畸变由3.35λ降到1.27λ;包含总能量95%的衍射极限倍数由6.21TDL降到了3.95TDL,说明焦斑能量集中度得到显著提高。
Experiments indicate that the size and shape of the final focal spot are mostly dictated by phase noise added to the beam. To diminish the static phase aberrations of large aperture lasers and promote the concentration degree of focal spot, phase corrector plate is proposed. For the technical integration line （TIL） being built in China Academy of Engineering Physics （CAEP）, phase aberration of the main amplifier is the largest contributor. Considering peak fluence of the inserting places and the machining process of the phase plate, four potential locations are evaluated, and the cavity mirror is chosen to be the preferred place and is replaced by the phase plate. Numerical calculation model is established to design the corrector plate. Cut-off frequency of the glass-slab filter is discussed and 0.01 mm^-1 is optimally chosen for the lowpass filter. The surface shape and the machining technique of the phase plate are given. Using SG99 light propagation code, simulations demonstrate that the corrector plate can effectively compensate optic finishing errors, and static phase aberration is decreased from 3. 35λto 1. 27λ. Further more, times diffraction limit （TDL） containing 95% energy of focal spot is improved from 6.21 to 3.95.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2006年第3期311-315,共5页
Chinese Journal of Lasers
基金
国家863计划(2005AA845030)资助项目
关键词
激光技术
静态相位控制元件
波前畸变
相位补偿
焦斑
laser technique
static phase control elements
wavefront aberration
phase correction
focal spot
