Planar ring resonator waveguides are fabricated in thin films of As2S3 chalcogenide glass,deposited on silicaon-silicon substrates.Waveguide cores are directly written by scanning the focused illumination of a femtose...Planar ring resonator waveguides are fabricated in thin films of As2S3 chalcogenide glass,deposited on silicaon-silicon substrates.Waveguide cores are directly written by scanning the focused illumination of a femtosecond Ti:sapphire laser at a central wavelength of 810 nm,through a two-photon photo-darkening process.A large photoinduced index change of 0.3–0.4 refractive index units is obtained.The radius of the ring resonator is 1.9 mm,corresponding to a transmission free spectral range of 9.1 GHz.A high loaded（intrinsic） Q value of 110,000（180,000） is achieved.The thermal dependence of the resonator transfer function is characterized.The results provide the first report,to the best of our knowledge,of directly written high-Q ring resonators in chalcogenide glass films,and demonstrate the potential of this simple technique towards the fabrication of planar lightguide circuits in these materials.展开更多
Objective: To investigate the effect of arsenic sulfide (tetra-arsenic tetra-sulfide As4S4; diarsenic trisulfide As2S3) on tissue factor (TF) expression and procoagulant activity (PCA) of acute promyelocytic leukemia(...Objective: To investigate the effect of arsenic sulfide (tetra-arsenic tetra-sulfide As4S4; diarsenic trisulfide As2S3) on tissue factor (TF) expression and procoagulant activity (PCA) of acute promyelocytic leukemia( APL) cell lines ( NB4 and MR2) and the basic mechanism of their role. Methods: NB4 and MR2 cells were respectively treated with As4S4 , As2S3, As4S4 and Cyclohexamide( CHX). PCA of the cells was detected using one-stage clotting assay. TF antigen was detected by ELISA. TF and PML/RARa fusion gene mRNA by semi-quantitive RT-PCR. The PCA and TF antigen of HL-60 and K562 cells were also examined. Results: The PCA and TF antigen level in NB4 and MR2 cells were significantly higher than that in HL-60 and K562 cells. Both As4S4 and As2S3 can down-regulate the TF antigen , TF mRNA transcription and membrane PCA of NB4 and MR2 cells in vitro in a time-dependent manner. The role of As4S4 was stronger than that of As2S3. Both As4S4 and As2S3 had no effect on PML/RARa fusion gene transcription. CHX treatment completely suppressed the down-regulate effect of As4S4 on the TF mRNA expression. Conclusion: As4S4 and As2S3 may down regulate tissue factor expression and PCA of NB4 and MR2 cells. By down-regulating TF expression, As4S4 and As2S3 might be used to improve the DIC-related hemorrhage in APL patients. Elevated TF antigen level of NB4 and MR2 cells may be related to the fusion gene PML/RARa. The modulation of the TF mRNA expression in NB4 and MR2 cells by As4S4 and As2S3 might be indirect and might not involve PML/RARa fusion gene.展开更多
We illustrate two As2S3 waveguide designs for four-wave mixing, which can generate 3.03 μm mid-infrared light from a 1.55 μm near-infrared signal source and a 2.05 μm pump source. Through simulations, we verify tha...We illustrate two As2S3 waveguide designs for four-wave mixing, which can generate 3.03 μm mid-infrared light from a 1.55 μm near-infrared signal source and a 2.05 μm pump source. Through simulations, we verify that four-wave mixing phase-matching efficiencies up to 100% can be achieved using dispersion engineering to maintain the dispersion at 2.05 μm near to zero. The best conversion efficiency is –10 dB. When the waveguide length is 1 cm, the parametric conversion bandwidth is 1525 nm. We also evaluated the shift of 100% phase-matching efficiency wavelengths based upon fabrication tolerances.展开更多
The homogeneous glass sample for the (1-x)As 2S 3-xCdBr 2,where x=0.015,0.035, 0.05, was prepared by the conventional melt-quenched method.Amorphous (1-x)As 2S 3-xCdBr 2 alloys were determined by X-...The homogeneous glass sample for the (1-x)As 2S 3-xCdBr 2,where x=0.015,0.035, 0.05, was prepared by the conventional melt-quenched method.Amorphous (1-x)As 2S 3-xCdBr 2 alloys were determined by X-ray diffraction, thermal comprehensive analysis and Raman scattering. The glass transition temperature (T g) decreases a bit with the addition of CdBr 2. Based on the experimental data, the microstructure is considered to be the discrete molecule species of AsBr 3 and Cd-S atomic bonds or clusters are homogeneously dispersed in a disordered polymer network formed by AsS 3 pyramids interlinked by sulfur bridges.展开更多
When femtosecond laser pulses interfere with chirped femtosecond laser pulses in As2S3 fiber, a chirped fiber grating is formed. An analytical expression is given to describe the chirped grating, and its Bragg reflect...When femtosecond laser pulses interfere with chirped femtosecond laser pulses in As2S3 fiber, a chirped fiber grating is formed. An analytical expression is given to describe the chirped grating, and its Bragg reflectivity is calculated. Because of the high photosensitive effect of As2S3 material, the chirped fiber grating has a wide Bragg reflective spectrum and high reflectivity by choosing proper parameters. This indicates that the chirped fiber grating can be used as a stretcher in the femtosecond chirped pulse amplification (CPA) system.展开更多
基金the support of the Israeli Science Foundation (ISF),under grant 635/10
文摘Planar ring resonator waveguides are fabricated in thin films of As2S3 chalcogenide glass,deposited on silicaon-silicon substrates.Waveguide cores are directly written by scanning the focused illumination of a femtosecond Ti:sapphire laser at a central wavelength of 810 nm,through a two-photon photo-darkening process.A large photoinduced index change of 0.3–0.4 refractive index units is obtained.The radius of the ring resonator is 1.9 mm,corresponding to a transmission free spectral range of 9.1 GHz.A high loaded（intrinsic） Q value of 110,000（180,000） is achieved.The thermal dependence of the resonator transfer function is characterized.The results provide the first report,to the best of our knowledge,of directly written high-Q ring resonators in chalcogenide glass films,and demonstrate the potential of this simple technique towards the fabrication of planar lightguide circuits in these materials.
基金Supported by Chinese Medicine Foundation of Shaanxi Province(No.1999002)
文摘Objective: To investigate the effect of arsenic sulfide (tetra-arsenic tetra-sulfide As4S4; diarsenic trisulfide As2S3) on tissue factor (TF) expression and procoagulant activity (PCA) of acute promyelocytic leukemia( APL) cell lines ( NB4 and MR2) and the basic mechanism of their role. Methods: NB4 and MR2 cells were respectively treated with As4S4 , As2S3, As4S4 and Cyclohexamide( CHX). PCA of the cells was detected using one-stage clotting assay. TF antigen was detected by ELISA. TF and PML/RARa fusion gene mRNA by semi-quantitive RT-PCR. The PCA and TF antigen of HL-60 and K562 cells were also examined. Results: The PCA and TF antigen level in NB4 and MR2 cells were significantly higher than that in HL-60 and K562 cells. Both As4S4 and As2S3 can down-regulate the TF antigen , TF mRNA transcription and membrane PCA of NB4 and MR2 cells in vitro in a time-dependent manner. The role of As4S4 was stronger than that of As2S3. Both As4S4 and As2S3 had no effect on PML/RARa fusion gene transcription. CHX treatment completely suppressed the down-regulate effect of As4S4 on the TF mRNA expression. Conclusion: As4S4 and As2S3 may down regulate tissue factor expression and PCA of NB4 and MR2 cells. By down-regulating TF expression, As4S4 and As2S3 might be used to improve the DIC-related hemorrhage in APL patients. Elevated TF antigen level of NB4 and MR2 cells may be related to the fusion gene PML/RARa. The modulation of the TF mRNA expression in NB4 and MR2 cells by As4S4 and As2S3 might be indirect and might not involve PML/RARa fusion gene.
文摘We illustrate two As2S3 waveguide designs for four-wave mixing, which can generate 3.03 μm mid-infrared light from a 1.55 μm near-infrared signal source and a 2.05 μm pump source. Through simulations, we verify that four-wave mixing phase-matching efficiencies up to 100% can be achieved using dispersion engineering to maintain the dispersion at 2.05 μm near to zero. The best conversion efficiency is –10 dB. When the waveguide length is 1 cm, the parametric conversion bandwidth is 1525 nm. We also evaluated the shift of 100% phase-matching efficiency wavelengths based upon fabrication tolerances.
文摘The homogeneous glass sample for the (1-x)As 2S 3-xCdBr 2,where x=0.015,0.035, 0.05, was prepared by the conventional melt-quenched method.Amorphous (1-x)As 2S 3-xCdBr 2 alloys were determined by X-ray diffraction, thermal comprehensive analysis and Raman scattering. The glass transition temperature (T g) decreases a bit with the addition of CdBr 2. Based on the experimental data, the microstructure is considered to be the discrete molecule species of AsBr 3 and Cd-S atomic bonds or clusters are homogeneously dispersed in a disordered polymer network formed by AsS 3 pyramids interlinked by sulfur bridges.
基金The authors acknowledge the support of the National Key Basic Research Special Foundation of China (No. G1999075201-2)the National Natural Science Foundation of China (No. 60178007)the Science Foundation of China for Post Ph. D (2002032163).
文摘When femtosecond laser pulses interfere with chirped femtosecond laser pulses in As2S3 fiber, a chirped fiber grating is formed. An analytical expression is given to describe the chirped grating, and its Bragg reflectivity is calculated. Because of the high photosensitive effect of As2S3 material, the chirped fiber grating has a wide Bragg reflective spectrum and high reflectivity by choosing proper parameters. This indicates that the chirped fiber grating can be used as a stretcher in the femtosecond chirped pulse amplification (CPA) system.
