We report the fabrication of a planar waveguide in the Nd：Bi_（12）SiO_（20） crystal by multi-energy C ions at room temperature. The waveguide is annealed at 200℃, 260℃, and 300℃ in succession each for 30 min in ...We report the fabrication of a planar waveguide in the Nd：Bi_（12）SiO_（20） crystal by multi-energy C ions at room temperature. The waveguide is annealed at 200℃, 260℃, and 300℃ in succession each for 30 min in an open oven. The effective refractive index profiles at transverse electric（TE） polarization are stable after the annealing treatments. Damage distribution for multi-energy C ion implanted in Nd：Bi_（12）SiO_（20） crystal is calculated by SRIM 2010. The Raman and fluorescence spectra of the Nd：Bi_（12）SiO_（20） crystal are collected by an excitation beam at 633 nm and 473 nm, respectively. The results indicate the stabilization of the optical waveguide in Nd：Bi_（12）SiO_（20） crystal.展开更多
The convection in melt crystal growth influences the crystal integrity deeply.During space crystal growth,the buoyancy driven convection has been eliminated for the microgravity environment,therefroe,surface tension d...The convection in melt crystal growth influences the crystal integrity deeply.During space crystal growth,the buoyancy driven convection has been eliminated for the microgravity environment,therefroe,surface tension driven convection (Marangoni Convection) become the main convection form.But the Marangoni convection forms,starting condition,development process and its influence on crystal growth are still unclear now.At the present time,Many studies focused on simulating liquid Marangoni convection or numerical simulation.However,few studies concerned on real melt,especially on oxide melt. In this paper,an in situ observation is carried out to study the start and development of Marangoni convection of Bi 12 SiO 20 melt in a 2mm diameter loop like platinum crucible.The different states of steady convection and the transition from steady to oscillatory convection are observed.The critical Marangoni number is obtained as 22433 and it agreed with a dependence Ma c=2884Pr 0.638 for high Prandtl number melt.The authors also obtained a dependence of convection oscillatory frequency on melt temperature.It increases with temperature rising.展开更多
Bi 12 TiO 20 (BTO)crystals have same structure as that of the Bi 12 SiO 20 (BSO)which is one of the most popular photorefractive materials.And both of them belong to cubic non centrosymmetric nonferroelectric material...Bi 12 TiO 20 (BTO)crystals have same structure as that of the Bi 12 SiO 20 (BSO)which is one of the most popular photorefractive materials.And both of them belong to cubic non centrosymmetric nonferroelectric materials.The cubic nonferroelectric oxides exhibit a number of advantages such as higher sensitivity and faster respond for applications in photorefractive.Compared to BSO,BTO have the largest electro optical coefficient and lower optical activity,especially it exhibits much high photosensitivity in the red light region that permits to use a cheap He Ne laser.It is,therefore,of high potential for applications in optical devices.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11404194 and 11274188)the Promotive Research Fund for Excellent Young and Middle-aged Scientisits of Shandong Province,China(Grant No.BS2015SF003)+3 种基金the China Postdoctoral Science Foundation(Grant Nos.2015M582053 and 2016T90609)the Qingdao Municipal Postdoctoral Application Research Project,China(Grant No.2015131)the State Key Laboratory of Nuclear Physics and Technology at Peking University,Chinathe State Key Laboratory of Crystal Materials and Key Laboratory of Particle Physics and Particle Irradiation(MOE)at Shandong University,China
文摘We report the fabrication of a planar waveguide in the Nd：Bi_（12）SiO_（20） crystal by multi-energy C ions at room temperature. The waveguide is annealed at 200℃, 260℃, and 300℃ in succession each for 30 min in an open oven. The effective refractive index profiles at transverse electric（TE） polarization are stable after the annealing treatments. Damage distribution for multi-energy C ion implanted in Nd：Bi_（12）SiO_（20） crystal is calculated by SRIM 2010. The Raman and fluorescence spectra of the Nd：Bi_（12）SiO_（20） crystal are collected by an excitation beam at 633 nm and 473 nm, respectively. The results indicate the stabilization of the optical waveguide in Nd：Bi_（12）SiO_（20） crystal.
文摘The convection in melt crystal growth influences the crystal integrity deeply.During space crystal growth,the buoyancy driven convection has been eliminated for the microgravity environment,therefroe,surface tension driven convection (Marangoni Convection) become the main convection form.But the Marangoni convection forms,starting condition,development process and its influence on crystal growth are still unclear now.At the present time,Many studies focused on simulating liquid Marangoni convection or numerical simulation.However,few studies concerned on real melt,especially on oxide melt. In this paper,an in situ observation is carried out to study the start and development of Marangoni convection of Bi 12 SiO 20 melt in a 2mm diameter loop like platinum crucible.The different states of steady convection and the transition from steady to oscillatory convection are observed.The critical Marangoni number is obtained as 22433 and it agreed with a dependence Ma c=2884Pr 0.638 for high Prandtl number melt.The authors also obtained a dependence of convection oscillatory frequency on melt temperature.It increases with temperature rising.
文摘Bi 12 TiO 20 (BTO)crystals have same structure as that of the Bi 12 SiO 20 (BSO)which is one of the most popular photorefractive materials.And both of them belong to cubic non centrosymmetric nonferroelectric materials.The cubic nonferroelectric oxides exhibit a number of advantages such as higher sensitivity and faster respond for applications in photorefractive.Compared to BSO,BTO have the largest electro optical coefficient and lower optical activity,especially it exhibits much high photosensitivity in the red light region that permits to use a cheap He Ne laser.It is,therefore,of high potential for applications in optical devices.
