Alkaline beryllium borate NaBeB(3)O(6) and ABe(2)B(3)O(7) (A = K, Rb) as UV nonlinear optical crystals.
A new series of alkaline beryllium borates NaBeB(3)O(6), alpha-KBe(2)B(3)O(7), beta-KBe(2)B(3)O(7), gamma-KBe(2)B(3)O(7), and RbBe(2)B(3)O(7) were synthesized by spontaneous crystallization with molten fluxes based on A(2)O-B(2)O(3) (A = Na, K, Rb) solvent. For KBe(2)B(3)O(7), three polymorphous phases were found and are referred to as alpha-, beta-, and gamma-KBe(2)B(3)O(7) relative to their crystallization temperature from high to low. All of the materials are noncentrosymmetric except alpha-KBe(2)B(3)O(7). NaBeB(3)O(6) and alpha-KBe(2)B(3)O(7) consist of a new anionic group [Be(2)B(3)O(11)](9-), which is similar to a naphthalene molecule that is rarely found in inorganic matter. beta-KBe(2)B(3)O(7), gamma-KBe(2)B(3)O(7), and RbBe(2)B(3)O(7) consist of 2D alveolate beryllium borate layers [Be(2)BO(5)](infinity), which are connected by strong covalent bonds. The UV-vis diffuse reflectance spectroscopy on powder samples indicated that the short-wavelength absorption edges of noncentrosymmetric materials are all below 200 nm. Second-harmonic generation (SHG) on powder samples was measured using the Kurtz and Perry technique, which indicated that NaBeB(3)O(6), beta-KBe(2)B(3)O(7), gamma-KBe(2)B(3)O(7), and RbBe(2)B(3)O(7) are all phase matchable materials, and their measured SHG coefficients were approximately 1.60, 0.75, 0.68, and 0.79 times as large as that of d(36) (KDP), respectively.
Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China.
Shichao
S
Wang
Ning
N
Ye
Wei
W
Li
Dan
D
Zhao