PREPARATION OF RARE EARTH ELEMENT DOPED GRADIENT INDEX GLASS

摘要

Radial gradient-index glass has been prepared by the sol-gel process using tetrabutoxytitanium as the source of index-modifying cation. Two systems have been studied. Wet gels were obtained by first partially hydrolyzing tetraethoxysilane (TEOS), then adding tetrabutoxytitanium alone or together with RE(NO_3)_3 into the mixture and using another part of water to hydrolyze the salts thoroughly and make it gel. The wet gels were then put into a H_2SO_4 or HNO_3 bath to partially leach out the index-modifying cations and form the concentration gradient. Through drying and sintering the gels were turned into transparent and colorless glass rods of about 4.5～7.5 mm in diameter. The resulting refractive index profile of the glass has been measured and the maximum index change from the center to the perimeter was about 0.03.