Spectral Absorptivity and Thermal Conductivity of BGO and BSO Melts and Single Crystals

Abstract

The present work describes the results of spectral absorptivity, α, and thermal conductivity, λ, studies for compound oxides SiO 20 in molten and monocrystalline states. The data for the spectral absorptivity were obtained by placing the sample onto a mirror and using the transmission method. To obtain the data on the thermal conductivity of crystals, the stationary method of two identical samples was used. The data for the thermal conductivity of melts were obtained by a new stationary relative method in which the thermal conductivity of the crystal is used as a reference. Special attention is focused on numerical and experimental error analysis at high temperature. The studies have shown that α in the range of a transmission band strongly depends on crystal purity. It varies from 0.0005 cm −1 to 0.03 cm −1 for Bi 4 Ge 3 O 12 and reaches 0.15 cm −1 for Bi 4 Si 3 O 12 . It was found that α is significantly greater for melts than for crystals, reaching (150 to 200) cm −1 for the Bi 4 Ge 3 O 12 melt. The thermal conductivity of the melts under investigation was found to be much smaller than that of the corresponding crystals.

Growth and Characterization of Single Crystalline Bi4Ge3O12Fibers for Electrooptic High Voltage Sensors

“…The absorption was essentially independent of the sample thickness. For comparison, recently reported data for conventionally grown bulk material were in the range of 0.0005 cm −1 to 0.03 cm −1 [28]. Figure 6: Electrooptic signal from a 150 mm long BGO sample versus applied alternating voltage (squares) and relative deviation from a linear fit (dots).…”

Revisiting the Luminescence Properties of Er3+, Tm3+ and Ho3+ Doped Bi4ge3o12 Rod-Type Crystal Fibers for the Laser Application

“…BGO crystals doped with transition metals of the iron group such as Cr, Mn, Fe and Co were studied for their photochromic and photorefractive behavior and their potential use in the production of optically induced holographic gratings [12][13][14][15]. BGO can also be doped rather easily with trivalent rare-earth ions and some of these rare-earth doped materials were investigated for lighting [16][17][18], temperature sensing [19] scintillating [20][21][22] and laser applications [23][24][25][26][27][28][29][30][31], the latter more specifically not only because of favorable emission properties but also because of several excellent optical, electrooptic and thermo-mechanical properties [23,[32][33][34] and because very stable, non-hygroscopic and high optical quality single crystals can be obtained in the form of large-size bulk materials as well as sub-millimeter rod-type crystal fibers by using well-mastered and low-temperature crystal growth techniques [1, [35][36][37]. This is not the case of many well-known reference laser materials for high power laser applications such as YLF (LiYF 4 ), YAG (Y 3 Al 5 O 12 ), YAP (YAlO 3 ) and (Y,Lu) 2 O 3 .…”