• Laser & Optoelectronics Progress
  • Vol. 56, Issue 19, 190002 (2019)
Huiwen Zong1、2、3、**, Jiangshan Zhao1、2、3、*, Xingliang Song1、2、3, Xin Guo1、2, Qian Wang1、2、3, Hui Li1、2, and Yi Zhou1、2、3
Author Affiliations
  • 1Department of Projection Optics, Academy of Opto-Electronics, Chinese Academy of Sciences, Beijing 100094, China
  • 2Beijing Excimer Laser Technology and Engineering Center, Beijing 100094, China
  • 3University of Chinese Academy of Sciences, Beijing 100049, China
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    DOI: 10.3788/LOP56.190002 Cite this Article Set citation alerts
    Huiwen Zong, Jiangshan Zhao, Xingliang Song, Xin Guo, Qian Wang, Hui Li, Yi Zhou. Development of Research on Damage Characteristics of Calcium Fluoride Crystal Under Deep Ultraviolet Laser Irradiation[J]. Laser & Optoelectronics Progress, 2019, 56(19): 190002 Copy Citation Text show less
    Structural diagram of CaF2 crystal
    Fig. 1. Structural diagram of CaF2 crystal
    CaF2 crystal. (a) Transmission spectrum; (b) relationship between refractive index and wavelength[4]
    Fig. 2. CaF2 crystal. (a) Transmission spectrum; (b) relationship between refractive index and wavelength[4]
    SEM images of laser-damaged CaF2. (a) Irradiated by ten ArF laser pulses (6.7 J/cm2); (b) irradiated by six ArF laser pulses (7.8 J/cm2)
    Fig. 3. SEM images of laser-damaged CaF2. (a) Irradiated by ten ArF laser pulses (6.7 J/cm2); (b) irradiated by six ArF laser pulses (7.8 J/cm2)
    SEM images of damage topographies of CaF2 (111) surfaces radiated by laser with different fluences. (a) Conventional standard polish,27.6 J/cm2; (b) diamond turned surface,30 J/cm2; (c) chemo-mechanically polished surface, 57.7 J/cm2; (d) terrace area of cleaved surface, 46 J/cm219
    Fig. 4. SEM images of damage topographies of CaF2 (111) surfaces radiated by laser with different fluences. (a) Conventional standard polish,27.6 J/cm2; (b) diamond turned surface,30 J/cm2; (c) chemo-mechanically polished surface, 57.7 J/cm2; (d) terrace area of cleaved surface, 46 J/cm219
    Time-resolved photoluminescence spectra of CaF2 specimen under excitation with ArF excimer laser pulse. (a) Excimer grade A; (b) excimer grade B; (c) UV grade[22]
    Fig. 5. Time-resolved photoluminescence spectra of CaF2 specimen under excitation with ArF excimer laser pulse. (a) Excimer grade A; (b) excimer grade B; (c) UV grade[22]
    ArF-induced absorption spectra of sodium-doped CaF2 crystal (sample A) and typical pure-CaF2 crystal (sample B)[25]
    Fig. 6. ArF-induced absorption spectra of sodium-doped CaF2 crystal (sample A) and typical pure-CaF2 crystal (sample B)[25]
    Laser induced damage thresholds under excitation of ArF excimer[28]
    Fig. 7. Laser induced damage thresholds under excitation of ArF excimer[28]
    Relationship between laser damage threshold and angle between laser polarization plane and crystal axis orientation of axis[29]
    Fig. 8. Relationship between laser damage threshold and angle between laser polarization plane and crystal axis orientation of <111> axis[29]
    Laser-induced damage probability as a function of fluence for F-SiO2 protective coating and F-SiO2 protected AR coating[39]
    Fig. 9. Laser-induced damage probability as a function of fluence for F-SiO2 protective coating and F-SiO2 protected AR coating[39]
    ParameterValueParameterValue
    Crystal density /(g·cm-3)3.180Melting point /℃1423
    Melt density /(g·cm-3)2.594Boiling point /℃2500
    Young's modulus /GPa89.80Thermal emissivity0.8
    Shear modulus /GPa33.77Expansion coefficient of heat /(10-6 K-1)18
    Volume modulus /GPa82.71Crystal thermal conductivity /(W·m-1·K-1)9.71
    Poisson's coefficient0.28Crystal heat transfer coefficient /(W·m-2·K-1)5
    Moh hardness4Melt heat transfer coefficient /(W·m-2·K-1)10
    Dielectric constant (1 MHz)6.76Specific heat (273 K) /(J·g-1·K-1)0.88
    Table 1. Physicochemical properties of CaF29,12
    SampleLaser induced damagethreshold @560 fsLaser induced damagethreshold @25 fs
    CaF21.816.1
    MgF21.716.2
    LiF20.3659.4
    BaF20.3419.4
    Suprasil1.996.85
    Table 2. Laser induced damage thresholds of ultraviolet transmitting crystals and fused silica
    Huiwen Zong, Jiangshan Zhao, Xingliang Song, Xin Guo, Qian Wang, Hui Li, Yi Zhou. Development of Research on Damage Characteristics of Calcium Fluoride Crystal Under Deep Ultraviolet Laser Irradiation[J]. Laser & Optoelectronics Progress, 2019, 56(19): 190002
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