Optical, thermo-optic, electro-optic, and photoelastic properties of bismuth germanate (Bi_4Ge_3O_12)

Abstract

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.

Bi3+ luminescence in ABiO2Cl (A=Sr, Ba) and BaBiO2Br

“…This work introduces photo-and radio-luminescence properties of these three members of the Sillen bismuth oxyhalide family. Their luminescence properties are compared to Bi 4 Ge 3 O 12 (BGO), an important material with electrooptic [16,17] , nonlinear optic [18] , and scintillation [2,7] capabilities. The preparation, photoluminescence, and time resolved x-ray luminescence of these compounds are detailed in this report.…”

Characterization of Bi4Ge3O12 single crystal by impedance spectroscopy

“…Bismuth germanate (Bi 4 Ge 3 O 12 -BGO), which has a cubic crystalline structure known as eulitine, has been demanded a great deal of interest due to its electro-optic, electro-mechanical and scintillator properties [1][2][3] . In particular, the use of BGO single crystals in electromagnetic measurements presents many advantages, since it possesses small temperature-dependence of electro-optic effect, high electrical resistivity, no optical activity, no natural birefringence and no pyroelectric effects 2,4 .…”

“…In particular, the use of BGO single crystals in electromagnetic measurements presents many advantages, since it possesses small temperature-dependence of electro-optic effect, high electrical resistivity, no optical activity, no natural birefringence and no pyroelectric effects 2,4 . The use of bismuth germanate as optical fiber sensor for simultaneous measurement of current and voltage was considered recently 5 and it was successfully tested for ac currents from 0.05 to 10 A and voltages from 1 to 235 V.…”

Electro-optic lightning detector

“…It is possible to arrange optics in such a way as to pass the laser light multiple times through the crystal to increase the total birefringence and thereby substantially improve sensor gain. We are also interested in inspecting other crystal types that offer certain advantages such as bismuth germanate (Bi4Ge3012) described in [32] and Hexamine ((CH2)6N4) described in [33].…”