摘要
应用于激光剥离、激光退火、激光转移等领域的大功率纳秒紫外激光器的输出激光通常是强度分布不均匀的部分相干光,为满足精密加工的高均匀度要求,开展了基于成像型微透镜阵列的紫外激光匀化技术研究。利用伪模分解理论和角谱衍射传输算法,建立了快速计算部分相干光通过微透镜阵列匀化系统的数值模型,并以准分子激光为仿真光源,通过对离焦量、阵列间距等参数的分析,确定了最佳设计参数,实现了边缘锐利的高均匀度方形光束输出。此外,详细讨论了微透镜阵列失调对光束形貌和均匀度的影响,并通过实验说明了理论设计的可靠性和参数影响分析的准确性。
Objective High-power nanosecond ultraviolet(UV)lasers have been widely applied in laser lift-off,laser annealing,laser transfer,and other fields,but their output is usually partially coherent light with nonuniform intensity distribution.To meet the high requirements of beam uniformity for precision machining,a homogenizer with microlens arrays is proposed.The microlens array homogenization technology based on the principle of beam splitting and superposition has attracted extensive attention due to its advantages of high energy utilization,insensitivity to wavelength,and good availability of unstable multimode beams.However,the current research on the homogenization technology of microlens arrays mostly adopts the ray tracing method of geometric optics,ignoring the diffraction effects that seriously affect the performance of homogenized beams,such as multi-beam interference and the finite aperture effect.Therefore,we design the microlens array homogenizer following the partially coherent diffraction principle and perform the quantization analysis of the influence of homogenizer parameters on the performance of output laser beams.Methods Partially coherent light can be described by the cross-spectral density function(CSD),but direct application of CSD to the simulation involves quadruple integral calculation,which takes a long time.Therefore,the pseudo-mode representation of CSD is used to simplify the numerical process and reduce computational time.By combining the pseudomode representation of partially coherent light and coherent light diffraction theory,we build a numerical simulation model of a microlens array homogenizer for high-power UV lasers and quantitatively analyze the parameters of the homogenizer.Specifically,an excimer laser source with different spatial coherence along the horizontal(short axis)and vertical(long axis)directions is represented as an incoherent superposition of mutually uncorrelated pseudo-modes,i.e.,the coherent plane-wave modes obtained from the Gaussian Schell-model(GSM).Then,the
作者
郑昕
戴深宇
张玉莹
赵帅
Zheng Xin;Dai Shenyu;Zhang Yuying;Zhao Shuai(Optoelectronics Science and Technology Research Department,Ji Hua Laboratory,Foshan 528200,Guangdong,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2023年第10期187-196,共10页
Acta Optica Sinica
基金
国家重点研发计划(2021YFB3602600)。
关键词
激光光学
紫外激光
部分相干光
激光匀化
微透镜阵列
失调
laser optics
ultraviolet laser
partially coherent light
laser homogenization
microlens array
misalignment
