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Design of the chirped multilayer mirrors in Extreme Ultraviolet region for ultrafast applications
被引:0
作者:
Wang, Fengli
[1
]
Liu, Lei
[1
]
Zhu, Jingtao
[1
]
Zhang, Zhong
[1
]
Li, Wenbin
[1
]
Wang, Zhanshan
[1
]
Chen, Lingyan
[1
]
机构:
[1] Tongji Univ, Dept Phys, Inst Precis Opt Engn, Shanghai 200092, Peoples R China
来源:
SEVENTH INTERNATIONAL CONFERENCE ON THIN FILM PHYSICS AND APPLICATIONS
|
2011年
/
7995卷
关键词:
Chirped multilayer;
group delay dispersion;
genetic algorithm;
reflectivity;
phase;
ATTOSECOND PULSES;
D O I:
10.1117/12.888421
中图分类号:
TB3 [工程材料学];
学科分类号:
0805 ;
080502 ;
摘要:
Chirped Mo/Si multilayer mirrors used in 13-17nm region have been designed using analytical approach based on the combination of genetic algorithm and simplex algorithm. The Cauchy equation and the polynomial expression were used to fit the real part and the imaginary part of the optical constants of Mo and Si in the wavelength region of 12.8-17.2nm, respectively. The reflectivity, reflective phase, group delay and group delay dispersion of the multilayer were calculated based on the Fresnel iterative equations. The initial structure of the multilayer was obtained by using the genetic algorithm, and the final structure of the mirror was optimized by using the simplex algorithm. We got the different multilayer mirrors for the target GDD of -2800 as(2), -3600 as(2), and -6500 as(2). For these three multilayer mirrors, the average reflectivities in the wavelength range of 13-17 nm are 7.00 +/- 0.08 %, 5.99 +/- 0.05 %, and 6.00 +/- 0.05 %, respectively. And the average GDD in the same wavelength range are -2793.22 +/- 104.00 as(2),-3597.44 +/- 79.06 as(2), and 6498.13 +/- 59.96 as(2). In addition, the effects of the interface roughness on the reflectivity and the phase were discussed. It is found that the reflectivity is sensitive to the interface roughness, but the phase is insensitive.
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页数:4
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