摘要
理解大口径光学系统离轴抛物面镜聚焦后超短脉冲时间信噪比(SNR)在焦斑处空间分布的特性有助于更准确地认识超快激光物理实验中的脉冲时空特性。利用空间上菲涅耳近似下的分两步聚焦的坐标变换快速傅里叶变换(FFT)算法,结合时间域的傅里叶积分变换方法,引入了光学系统波前误差,对聚焦过程进行时空仿真。解释了大口径光学系统波前误差造成时间信噪比退化的原因,计算分析随机波前误差参数(误差大小、空间尺度)对聚焦时间信噪比的影响,并针对不同频段的光学系统波前误差控制提出要求。明确大口径光学系统中随机波前误差与时间信噪比之间的关系,为大口径超短脉冲系统的设计指标分配与波前误差控制提供了理论基础。
Understanding of the spatial distribution of ultrashort pulse temporal signal-to-noise ratio （SNR） characteristics at the focal spot in large aperture off-axis parabolic mirror focusing optical system is helpful for more accurate understanding of ultrafast laser pulse temporal and spatial characteristics in the ultrafast laser physics experiments. With wave-front error of optical system under consideration, the two-step focusing fast Fourier transform （FFT） algorithm with the coordinate transform based on Fresnel approximation in space domain and Fourier integral transform method in time domain are used to simulate the focusing process spatially and temporally. SNR degradation by wave-front error in large aperture optical system is explained, SNR ratio characteristics influenced by the parameters of the random wave-front error such as error magnitude and space scale are calculated and analyzed, and control requirements for different spectra of optical wave-front error of optical system are put forward. Explicating the relationship between SNR and random wave-front error in large diameter optical system is theoretical basis of designing large aperture ultrashort pulse system and wave-front error control.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2014年第10期322-328,共7页
Acta Optica Sinica
基金
国家863计划(2013AA8044010)
关键词
超快光学
时间信噪比
波前误差
傅里叶变换
坐标变换
ultrafast optics
temporal signal-to-noise ratio
wave-front error
Fourier transform
coordinate transform
