Abstract

This paper discusses films of nanosize particles obtained on the surface of ionic crystals of CaF2 and BaF2 with impurities of rare-earth metals Eu, Ce, Sm, and Tm during the thermal diffusion of an intracrystalline impurity. After the CaF2 crystals are annealed, two bands appear in their optical spectra, with maxima around 270-280 nm and 390 nm, which disappear after a thin surface layer is removed. The surface centers have intense bands at 1100-1150 cm⁻¹ and 3640 cm⁻¹ and a moderately intense broad band at 3100-3700 cm⁻¹ in the IR spectra of the CaF2 crystals. Intense bands appear at 855-960 cm⁻¹ in the IR spectrum of the heat-treated BaF2:Ce crystal, along with the bands at 1100-1150 cm⁻¹, 3640 cm⁻¹, and 3100-3700 cm⁻¹. It is established that the surface centers include impurity ions of a rare-earth metal and the thermal-decomposition products of atmospheric gases.

Vacuum ultraviolet spectra of CaF₂:Eu⁺³ and CaF₂:Sm⁺³

M. Schlesinger and T. Szczurek
J. Opt. Soc. Am. 70(8) 1025-1029 (1980)

Spectroscopic characteristics, continuous-wave and mode-locking laser performances of Tm,Y:CaF₂ disordered crystal

Lingchen Kong, Zhen Qiao, Guoqiang Xie, Zhipeng Qin, Beibei Zhao, Hao Yu, Liangbi Su, Jingui Ma, Peng Yuan, and Liejia Qian
Opt. Express 25(18) 21267-21274 (2017)

Bi-doped BaF₂ crystal for broadband near-infrared light source

Jian Ruan, Liangbi Su, Jianrong Qiu, Danping Chen, and Jun Xu
Opt. Express 17(7) 5163-5169 (2009)

Temperature dependence of photoluminescence in SrS:Eu²⁺, Sm³⁺ thin films

Z. Hua, L. Salamanca-Riba, M. Wuttig, and P. K. Soltani
J. Opt. Soc. Am. B 10(8) 1464-1469 (1993)

Time-resolved photoluminescence for diagnosis of resistance to ArF excimer laser damage to CaF₂ single crystals

Masafumi Mizuguchi, Hideo Hosono, Hiroshi Kawazoe, and Tohru Ogawa
J. Opt. Soc. Am. B 16(7) 1153-1159 (1999)