Williams P A, Rose A H, Lee K S, Conrad D C, Day G W, Hale P D
Appl Opt. 1996 Jul 1;35(19):3562-9. doi: 10.1364/AO.35.003562.
To assess the suitability of bismuth germanate as an electro-optic material for high precision applications, we have confirmed and extended previous data on its refractive index, electro-optic tensor element r(41), and thermal expansion coefficient. In addition, we have measured the thermo-optic coefficient dn/dT, the temperature dependence of the electro-optic coefficient, and the stress-optic tensor elements. From the stress-optic tensor elements and previously published data, we have computed the strain-optic tensor elements. The index of refraction is given, to a good approximation, by the single-term Sellmeier equation, n(2) - 1 = S(0)λ(0)(2)/[1 - (λ(0)/λ)(2)], with S(0) = 95.608 µm(-2) and λ(0) = 0.1807 µm. The thermo-optic coefficient is 3.9 × 10(-5)/°C at 632.8 nm and 3.5 × 10(-5)/°C at 1152.3 nm. The electro-optic tensor element varies between approximately 1.05 and 1.11 pm/V over the spectral range of 550-1000 nm; its normalized effective change with temperature is approximately 1.54 × 10(-4)/°C. The thermal expansion coefficient is 6.3 × 10(-6)/°C over the range 15-125 °C. Values of the stress-optic tensor elements are q(11) - q(12) = -2.995 × 10(-13) m(2)/N and q(44) = -0.1365 × 10(-12) m(2)/N. The strain-optic tensor elements are p(11) - p(12) = -0.0266 and p(44) = -0.0595.
为评估锗酸铋作为一种适用于高精度应用的电光材料的适用性，我们已确认并扩展了先前关于其折射率、电光张量元素r(41)和热膨胀系数的数据。此外，我们还测量了热光系数dn/dT、电光系数的温度依赖性以及应力光学张量元素。根据应力光学张量元素和先前发表的数据，我们计算了应变光学张量元素。折射率在很好的近似下由单一项Sellmeier方程给出，n(2) - 1 = S(0)λ(0)(2)/[1 - (λ(0)/λ)(2)]，其中S(0) = 95.608 µm(-2)且λ(0) = 0.1807 µm。在632.8 nm处热光系数为3.9 × 10(-5)/°C，在1152.3 nm处为3.5 × 10(-5)/°C。电光张量元素在550 - 10,000 nm光谱范围内约在1.05至1.11 pm/V之间变化；其随温度的归一化有效变化约为1.54 × 10(-4)/°C。在15 - 125 °C范围内热膨胀系数为6.3 × 10(-6)/°C。应力光学张量元素的值为q(11) - q(12) = -2.995 × 10(-13) m(2)/N且q(44) = -0.1365 × 10(-12) m(2)/N。应变光学张量元素为p(11) - p(12) = -0.0266且p(44) = -0.0595。 （注：原文中“10,000 nm”疑似有误，根据前文推测可能是“1000 nm”，已按此翻译）
