Study on th growth of nonlinear optical crystal $CsLiB_{6}O_{10}$

비선형 광학 결정 $CsLiB_{6}O_{10}$ 육성에 관한 기초 연구

  • Published : 1996.05.01

Abstract

The fundamental conditions for growing $CsLiB_{6}O_{10}$ crystal, new nonlinear optical material, were investigated. Stoichiometirc mixture of $CsLiB_{6}O_{10}$ composition resulted in the crystal of the same composition in the process of heating at the temperature above $600^{\circ}C$. No phase transition was observed in the $CsLiB_{6}O_{10}$ crystal in the temperature range of $600^{\circ}C~800^{\circ}C$, and $CsLiB_{6}O_{10}$ crystal melted congruently at $850^{\circ}C$. When the melt of this composition was cooled at rates of $1~150^{\circ}C/hr$, glass state ingot was formed regardless of cooling rates. However, $CsLiB_{6}O_{10}$ crystals were formed directly from the melt at any cooling rate in the presence of $CsLiB_{6}O_{10}$ seed crystal in the melt. Transparent $CsLiB_{6}O_{10}$ single crystal was grown from the melt using the seed crystal at the growing rate of 0.06 mm/hr in the furnace having the temperature gradient of $100^{\circ}C/cm$. Analysis of the single crystal showed that the crystal belonged to the noncentrosymmetric tetragonal space group 142d and unit cell dimensions were $a=10.467(1)\;{\AA},\;c=8.972(1)\;{\AA}\;and\;V=983.0(2)\;{\AA}^3$. Optical absorption edge of the crystal was observed at 180mm and the crystal showed a good optical transparency (70% transmittance, sample thickness 0.5 mm) in the wide wavelength range above 300 nm.

새로운 비선형 광학결정으로 유망시되는 $CsLiB_{6}O_{10}$ 결정을 육성하기 위한 기초 조건을 조사하였다. 화학양론적으로 혼합된 $CsLiB_{6}O_{10}$ 조성으로부터 $600^{\circ}C$ 이상의 온도에서 같은 조성의 결정이 형성되었고, 이 결정은 $800^{\circ}C$까지 상변화를 나타내지 않았으며, $850^{\circ}C$에서 합치용융하였다. $CsLiB_{6}O_{10}$ 조성을 용융시킨 뒤, 융액을 $1~150^{\circ}C/hr$의 냉각 속도로 냉각시키면, 냉각 속도에 관계없이 유리가 생성되었다. 그러나 융액중에 $CsLiB_{6}O_{10}$ 결정 seed가 존재하는 경우에는 융액으로부터 $CsLiB_{6}O_{10}$ 결정이 직접 석출되었다. Seed 결정을 이용하여 온도 구배가 $100^{\circ}C/cm$인 일방향 전기로에서 0.06 mm/hr의 응고 속도로 투명한 $CsLiB_{6}O_{10}$ 단결정을 육성하였다. 육성된 결정의 구조 해석 결과, 이결정은 noncentrosymmetric tetragonal space group 142d에 속하고, unit cell dimensions은 $a=10.467(1)\;{\AA},\;c=8.972(1)\;{\AA}과\;V=983.0(2)\;{\AA}^3$이었다. 이 결정의 광학적 특성은 180mm에서 absorption edge를 가지고 300 nm이상의 파장 영역에서 70%의 광투과율(두께 0.5 mm)을 나타내었다.

Keywords

References

  1. Nonlinear Optical Processes In Encyclopedia of Laser and Optical Technology J. F. Reintjes
  2. Phys. Chem. Glasses v.32 no.6 E. M. Vogel;M. H. Weber;D. M. Krol
  3. Measurement Technique for Third-order Non-linear Optical Effects in Introduction to Nonlinear Optical Effects in Molecule and Polymers P. N. Prasad;D. J. Williams
  4. Nonlinear Optics v.1 S. Sudo
  5. Nonlinear Optics v.1 T. Kobayashi
  6. Appl. Opt. v.26 no.2 D. H. Auston(et al.)
  7. Inorganic Nonlinear Optic Crystals New Glass v.3 no.4 T. Taniuchi
  8. J. Appl. Phys. v.62 D. Eimerl;L. Davis;S. Velsko;E. K. Gram;A. Zalkin
  9. Ferroelec. v.72 D. Eimerl
  10. Material Research Bulletine v.30 no.2 J. M. Tu;D. A. Keszler
  11. Jpn. J. Appl. Physics v.34 Y. Mori(et al.)
  12. Acta Crystallogr v.A46 G. M. Sheldrick
  13. J. Appl. Cryst. G. M. Sheldrick
  14. J. Appl. Physics v.37 J. D. Hunt;K. A. Jackson
  15. Solidification Processing M. C. Flemings
  16. Acta Crystallogr v.A32 Shannon, R. D
  17. Basic Solid State Chemistry A. R. West
  18. Infra Red and Raman Spectra of Inorganic and Coordination Compound (4th Ed.) K. Nakamoto
  19. Chines Phys. Lett. v.2 C. T. Chen;Y. C. Wu;R. K. Li