摘要
相位光栅(PG)标记是微位移测量系统的关键部件,提出了一种严格耦合波(RCWA)法与差分进化算法相结合的共振域PG标记设计方法,解决了标量衍射理论计算精度不足和参数遍历设计方法耗时太久的问题。基于自参考干涉位移测量模型,确定以测量光信噪比(SNR)之和最大为光栅标记设计的评价函数,并研究了不同入射光波长、偏振态和光栅周期下,RCWA法中空间谐波数与计算精度的关系。针对多波长照明微位移测量需求,利用所提方法进行了标记设计,并与常规设计方法进行了比对分析。结果表明:对于3.2μm周期的PG,横磁(TM)光照射时光栅占空比取0.484,槽深取161.5 nm,此时SNR之和可达到最大值586.63;较常规设计方法,所提方法设计PG标记的时间缩短到了其的0.2%,SNR之和最大提升比例可达到24.4%。
Phase grating(PG)mark is a key component of a microdisplacement measurement system.In this paper,a design method of PG mark in resonance domain combining rigorous coupled wave analysis(RCWA)method with differential evolution algorithm is proposed to address issues including insufficient calculation accuracy of scalar diffraction theory and time consuming of parameter traversal design method.Firstly,according to the selfreference interference displacement measurement model,the maximum sum of measured optical signaltonoise ratio(SNR)is regarded as the evaluation function of grating mark design.The relationship between the number of spatial harmonics and calculation accuracy in RCWA method is studied under different incident light wavelengths,polarization states,and grating periods.In view of the measurement requirement of multiwavelength illumination microdisplacement,the proposed method is used to design the mark,and it is compared with conventional design methods.The results show that for the PG with period of 3.2μm,the duty cycle of the grating is 0.484,and the groove depth is 161.5 nm under transverse magnetic(TM)light.Furthermore,the sum of SNR reaches the maximum value of 586.63.Compared with conventional design methods,the proposed method shortens the time in designing the PG mark to 0.2%,and the maximum improvement ratio of the sum of SNR reaches 24.4%.
作者
周光迎
齐月静
齐威
卢增雄
苏佳妮
Zhou Guangying;Qi Yuejing;Qi Wei;Lu Zengxiong;Su Jiani(Institute of Microelectronics of Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2022年第21期106-113,共8页
Acta Optica Sinica
基金
国家科技重大专项(2018ZX02101005)。
关键词
光栅
位移测量系统
严格耦合波法
空间谐波数
差分进化算法
gratings
displacement measurement system
rigorous coupled wave analysis method
spatial harmonic number
differential evolution algorithm
