GUO Chun LI Bin-cheng. Determination of refractive index and thickness of MgF<sub>2</sub> film using simulated annealing algorithm[J]. Editorial Office of Optics and Precision Engineering, 2013,21(4): 858-863
GUO Chun LI Bin-cheng. Determination of refractive index and thickness of MgF<sub>2</sub> film using simulated annealing algorithm[J]. Editorial Office of Optics and Precision Engineering, 2013,21(4): 858-863 DOI: 10.3788/OPE.20132104.0858.
Determination of refractive index and thickness of MgF2 film using simulated annealing algorithm
This paper focused on the method to determine the physical thickness of a single-layer MgF
2
film and its refractive index in the deep ultraviolet/vacuum ultraviolet spectral ranges. The single-layer MgF
2
film was prepared on the B270 substrate by a Mo boat evaporation method. On the basis of reflectance spectra of the single-layer MgF
2
film at various incidence angles
the refractive index and thickness of the film in 170-260 nm were determined by the simulated annealing algorithm and were compared with those of determined by ellipsometry. Experimental results indicate that the thicknesses of the MgF
2
film are 248.5 nm and 249.5 nm by the simulated annealing algorithm and ellipsometry
respectively
which shows a deviation of 0.4%. Moreover
the refractive indexes of the MgF
2
film at 240-260 nm obtained by two method mentioned above show a deviation less than 0.003. Obtained results prove that the method employing the reflectance spectral and simulated annealing is reliable for determining the refractive index and thickness of the MgF
2
film.
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