| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2004: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2002: ¥2,300,000 (Direct Cost: ¥2,300,000)
|
|---|
| Research Abstract |
Development of a suitable material with high second-order non-linear optical constant is important to obtain high performance wavelength converter. Heavy metals increase non-linearity of optical glass materials. This research project has studied selection of a suitable material in tellurite glass systems, which has a potential of high second-order non-linearity, from the view pint of glass forming properties and measuring optical characteristics. We investigated glass formation region on TeO_2-WO_3-X(X=La_2O_3,Nb _2O_5,Bi_2O_3,PbO, Ta_2O_5,TiO_2) systems, by casting melts on a mold of iron. Then we polished them into an optical flat plate sample with 0.5mm thickness. It was the TeO_2-WO_3-La_2O_3 and TeO_2-WO_3-PbO systems, which has wider glass forming region and clearer transparency. Especially, in the TeO_2-WO_3-La_2O_3 system, coloration phenomenon was observed and was depending on the glass composition. UV absorption edge is 375nm for light yellowed TeO_2-WO_3-La_2O_3(20mol%) and 420nm for browned TeO_2-WO_3-La_2O_3(10mol%), respectively. Coloration is depending on the molar concentration of La_2O_3 clearly. It seems that the reaction, WO_3(yellow)→WO_2(brown) in glass melting, is suppressed by the increasing of La_2O_3 content where impurity of CeO_2 in La_2O_3 acts as oxidizing reagent. The relationship among glass composition, absorption edge and nonlinear optical properties was clarified by measuring UV-VIS transparency and third-harmonic generation(THG) characteristics for various glass materials. THG constant is 0.28-1.6(x10^<-12>esu) for these tellurite glasses. It is concluded that TeO_2-WO_3- X(X=PbO, La_2O_3) glass system is useful as a material for high performance wavelength converter. We have also tried poling of TeO_2-WO_3PbO glasses. We have succeeded to observe SHG phenomenon ot these tellurite glasses and found that its SHG constant is relatively high as 54pm/V.
|
