Tsai, C. N.C. N.TsaiLin, Y. S.Y. S.LinHuang, K. Y.K. Y.HuangLai, C. C.C. C.LaiSHENG-LUNG HUANG2010-09-272018-07-052010-09-272018-07-05200800214922http://ntur.lib.ntu.edu.tw//handle/246246/205573https://www.scopus.com/inward/record.uri?eid=2-s2.0-55149124727&doi=10.1143%2fJJAP.47.6369&partnerID=40&md5=a80ff10f66491a48c41b041eeae6b33eChromium ions tend to diffuse outward during the laser-heated pedestal growth (LHPG) of Y3Al5O12 (YAG) crystal fiber, in which the average Cr4+ ion concentration decreases significantly after each diameter-reduction step. The Cr4+ ions are replenished using an electron gun to deposit Cr2O3 and divalent-ion oxide (CaO or MgO) on the source rod circumference before LHPG. It was observed that Ca2+ has better efficiency to diffuse into the source rod more efficiently than Mg2+ generating fewer defects and stacking faults. By CaO deposition and post growth annealing at 1350°C under an oxygen environment, a 110% increase in Cr4+ concentration was obtained. The achieved Cr4+ concentration and the ratio of Cr4+ to total Cr were 1.76 × 1018 cm-3 and 5.5, respectively. The Ca,Cr:YAG crystal fiber can thus be used as an ultra broadband laser material and amplified spontaneous emitter. © 2008 The Japan Society of Applied Physics.en-USCr4+:YAG; Crystal fiber; Deposition; Doping; Laser-heated pedestal growthAnnealing; Calcium; Concentration (process); Crystal whiskers; Electrolysis; Electron beams; Electron guns; Electron tubes; Fibers; Ions; Lasers; Metal ions; Oxygen; Powders; Stacking faults; Chromium ions; Cr:yag crystals; Cr4+:YAG; Crystal fiber; Crystal fibers; Doping; Ion concentrations; Ion oxides; Oxygen environments; Pedestal growths; Reduction steps; Ultra broadbands; Chromiumjournal article10.1143/JJAP.47.63692-s2.0-55149124727http://ntur.lib.ntu.edu.tw/bitstream/246246/205573/1/901.pdf