To our knowledge, we have demonstrated for the first time that (2+1)-dimension photorefractive waveguides can be written and stored by light using the (2+1)-dimension photovoltaic dark spatial solitons in LiNbO3:Fe cr...To our knowledge, we have demonstrated for the first time that (2+1)-dimension photorefractive waveguides can be written and stored by light using the (2+1)-dimension photovoltaic dark spatial solitons in LiNbO3:Fe crystals. It can guide a probe beam of the same wavelength as that of the writing beam.展开更多
A novel symmetric plasmonic structure consisting of a metal-insulator-metal waveguide and a rectangular cavity is proposed to investigate Fano resonance performance by adjusting the size of the structure.The Fano reso...A novel symmetric plasmonic structure consisting of a metal-insulator-metal waveguide and a rectangular cavity is proposed to investigate Fano resonance performance by adjusting the size of the structure.The Fano resonance originates from the interference between a local quadrupolar and a broad spectral line in the rectangular cavity.The tuning of the Fano profile is realized by changing the size of the rectangular cavity.The nanostructure is expected to work as an excellent plasmonic sensor with a high sensitivity of about 530 nm/RIU and a figure of merit of about 650.展开更多
We observed the photorefractive spatial dark-soliton stripes In LiNbO3:Fe crystal,and demonsirate the planar waveguide property of refractive index proiile induced by these spatial dark-soli ton stripes.We suggest a n...We observed the photorefractive spatial dark-soliton stripes In LiNbO3:Fe crystal,and demonsirate the planar waveguide property of refractive index proiile induced by these spatial dark-soli ton stripes.We suggest a new mothed to form the planar waveguide utilizing the grating fixing technique.展开更多
The nanocrystalline SiC films were prepared on Si then annealed at 800℃ and 1 000℃ for 30 minutes （111） substrates by rf magnetron sputtering and in a vacuum annealing system. The crystal structure and crystalliza...The nanocrystalline SiC films were prepared on Si then annealed at 800℃ and 1 000℃ for 30 minutes （111） substrates by rf magnetron sputtering and in a vacuum annealing system. The crystal structure and crystallization of as-annealed SiC films were determined by the Fourier transform infrared （FIR） absorption spectra and the X-ray diffraction （XRD） analysis. Measurement of photoluminescence （PL） of the nanocrystalline SiC （nc-SiC） films shows that the blue light with 473 nm and 477 nm wavelengths emitted at room temperature and that the PL peak shifts to shorter wavelength side and the PL intensity becomes stronger as the annealing temperature decreases. The time-resolved spectrum of the PL at 477 nm exhibits a bi-exponential decay process with lifetimes of 600 ps and 5 ns and a characteristic of the direct band gap. The strong blue light emission with short PL lifetimes suggests that the quantum confinement effect of the SiC nanocrystals resulted in the radiative recombination of the direct optical transitions.展开更多
The luminescent properties of Er^(3+) ions in LiNbO_(3):Er and LiNbO_(3):Mg, Er crystals at room temperature have been investigated by the emission spectra and the selective excitation spectra. The energy transition p...The luminescent properties of Er^(3+) ions in LiNbO_(3):Er and LiNbO_(3):Mg, Er crystals at room temperature have been investigated by the emission spectra and the selective excitation spectra. The energy transition processes of Er3+ luminescence have been analysed. It has been found that the luminescent intensity of Er^(3+) ions in the LiNbO_(3):Mg, Er crystal increased up to 7.8 times compared with that in the LiNbO_(3):Er crystal. The decrease of the defect centre (NbLi) concentration due to doping with Mg^(2+) ions plays a key role in this phenomenon.展开更多
The typical laser characteristics of a laser diode pumped,solid-state laser with a Z-type resonator structure are analyzed by the transform circle approach.Laser waists change with the thennal focus length of the lasi...The typical laser characteristics of a laser diode pumped,solid-state laser with a Z-type resonator structure are analyzed by the transform circle approach.Laser waists change with the thennal focus length of the lasing medium so that the output power becomes unstable.In particular,there is a very unstable operation region when the pump power is of medium magnitude.A method is put forward to avoid this situation.展开更多
The domain reversal characteristics of near-stoichiometric LiNbO3 ([Li]/[Li+Nb]=0.496) single crystals, which are grown by the Czochralski method with K2O tlux, are investigated. The switch tield for 180° ferroel...The domain reversal characteristics of near-stoichiometric LiNbO3 ([Li]/[Li+Nb]=0.496) single crystals, which are grown by the Czochralski method with K2O tlux, are investigated. The switch tield for 180° ferroelectric domain reversal in the near-stoichiometric LiNbO3 crystal is 8.0±0.5kV/mm, which is only one third of the switching field required for the congruent LiNbO3 crystals. We have successfully achieved 180° domain reversal in near-stoichiometric LiNbO3 samples of 1.0mm thickness.展开更多
A new method to suppress the fanning noise caused by He-Ne laser in the cooperation with Ar+laser in photorefractive LiNbO_(3):Fe crystal was successfully realized.This method is simple and efficient.By using this met...A new method to suppress the fanning noise caused by He-Ne laser in the cooperation with Ar+laser in photorefractive LiNbO_(3):Fe crystal was successfully realized.This method is simple and efficient.By using this method,fanning-noise-free hologram can be stored in LiNbO_(3):Fecrystal.展开更多
Beam manipulation by metallic nanoslit arrays with perpendicular cuts inside the slits was investigated numerically.The simulated results performed by the finite element method(FEM)show that perpendicular cuts with di...Beam manipulation by metallic nanoslit arrays with perpendicular cuts inside the slits was investigated numerically.The simulated results performed by the finite element method(FEM)show that perpendicular cuts with different heights can modulate phase retardation of the transmitted light through the slits.With the proper distribution of cut height,a focused beam is achieved in our metallic nanostructure with four-time amplitude at the focus point and half focal length compared to a slit array without cuts inside.By using asymmetric distribution of height amplitude,a beam deflection around 6°can also be realized in our design.展开更多
The steady intensity of a forward phase conjugate wave (FPCW) is successfully observed along the c-axis in the highly magnesium-doped lithium niobate crystal. We put forward a detailed physical picture for our experim...The steady intensity of a forward phase conjugate wave (FPCW) is successfully observed along the c-axis in the highly magnesium-doped lithium niobate crystal. We put forward a detailed physical picture for our experiment phenomena. The FPCW is generated from the phase-mismatch in a three-wave coupling process, and tends to be stable accompanied with the building of photorefractive gratings and four-wave coupling processes. Our experimental result is also discussed and analysed by means of the wave coupling theory, and the theoretical expression is provided for the experiment.展开更多
Light-induced absorption in the nominally pure bismuth silicon oxide is investigated experimentally and the result shows that it consists of transient and persistent parts. The experimental evidence is analysed based ...Light-induced absorption in the nominally pure bismuth silicon oxide is investigated experimentally and the result shows that it consists of transient and persistent parts. The experimental evidence is analysed based on the model of three groups of trap (donor) centres.展开更多
基金Supported by the Third World Academy of Science,the National Natural Science Foundation of Chinathe Key Reseach Project in Climbing Program from the State Science and Technologe Commission of China。
文摘To our knowledge, we have demonstrated for the first time that (2+1)-dimension photorefractive waveguides can be written and stored by light using the (2+1)-dimension photovoltaic dark spatial solitons in LiNbO3:Fe crystals. It can guide a probe beam of the same wavelength as that of the writing beam.
基金the National Natural Science Foundation of China under Grant No 61178004the Tianjin Natural Science Foundation under Grant No 12JCQNJC01100+1 种基金the Doctoral Program of Higher Education of China under Grant No 20110031120005the Program for Changjiang Scholars and Innovative Research Team in Nankai University.
文摘A novel symmetric plasmonic structure consisting of a metal-insulator-metal waveguide and a rectangular cavity is proposed to investigate Fano resonance performance by adjusting the size of the structure.The Fano resonance originates from the interference between a local quadrupolar and a broad spectral line in the rectangular cavity.The tuning of the Fano profile is realized by changing the size of the rectangular cavity.The nanostructure is expected to work as an excellent plasmonic sensor with a high sensitivity of about 530 nm/RIU and a figure of merit of about 650.
基金Supported by the Third World Academy of Sciencesthe National Natural Science Foundation of Cliinathe Key Research Project in Climbing Program from the State Science and Technology Commission of China.
文摘We observed the photorefractive spatial dark-soliton stripes In LiNbO3:Fe crystal,and demonsirate the planar waveguide property of refractive index proiile induced by these spatial dark-soli ton stripes.We suggest a new mothed to form the planar waveguide utilizing the grating fixing technique.
基金The project supported by the National Natural Science Founda-tion of China(Grant No.60476003)
文摘The nanocrystalline SiC films were prepared on Si then annealed at 800℃ and 1 000℃ for 30 minutes （111） substrates by rf magnetron sputtering and in a vacuum annealing system. The crystal structure and crystallization of as-annealed SiC films were determined by the Fourier transform infrared （FIR） absorption spectra and the X-ray diffraction （XRD） analysis. Measurement of photoluminescence （PL） of the nanocrystalline SiC （nc-SiC） films shows that the blue light with 473 nm and 477 nm wavelengths emitted at room temperature and that the PL peak shifts to shorter wavelength side and the PL intensity becomes stronger as the annealing temperature decreases. The time-resolved spectrum of the PL at 477 nm exhibits a bi-exponential decay process with lifetimes of 600 ps and 5 ns and a characteristic of the direct band gap. The strong blue light emission with short PL lifetimes suggests that the quantum confinement effect of the SiC nanocrystals resulted in the radiative recombination of the direct optical transitions.
基金Supported by the National Advanced Material Commit tee of China under Grant No.863-715-001-0102by the fund for the excellent young researchers from the National Natural Science Foundation of China+1 种基金the National Education Ministry of China under Grants Nos.69825108 and 19734004“973”project China under Grant No.G1999033003.
文摘The luminescent properties of Er^(3+) ions in LiNbO_(3):Er and LiNbO_(3):Mg, Er crystals at room temperature have been investigated by the emission spectra and the selective excitation spectra. The energy transition processes of Er3+ luminescence have been analysed. It has been found that the luminescent intensity of Er^(3+) ions in the LiNbO_(3):Mg, Er crystal increased up to 7.8 times compared with that in the LiNbO_(3):Er crystal. The decrease of the defect centre (NbLi) concentration due to doping with Mg^(2+) ions plays a key role in this phenomenon.
基金Supported by Tianjin Natural Science Foundation under Grant No.99380111the National Natural Science Foundation of China under Grant No.69825108。
文摘The typical laser characteristics of a laser diode pumped,solid-state laser with a Z-type resonator structure are analyzed by the transform circle approach.Laser waists change with the thennal focus length of the lasing medium so that the output power becomes unstable.In particular,there is a very unstable operation region when the pump power is of medium magnitude.A method is put forward to avoid this situation.
基金Supported by the National Advanced Material Committee(grant 863-715-001-0102)and special funding for the excellent young researchers from the National Natural Science Foundation of China under Grant No.69825108and National Education Ministry of China,“973”Project(grant 1999033004).
文摘The domain reversal characteristics of near-stoichiometric LiNbO3 ([Li]/[Li+Nb]=0.496) single crystals, which are grown by the Czochralski method with K2O tlux, are investigated. The switch tield for 180° ferroelectric domain reversal in the near-stoichiometric LiNbO3 crystal is 8.0±0.5kV/mm, which is only one third of the switching field required for the congruent LiNbO3 crystals. We have successfully achieved 180° domain reversal in near-stoichiometric LiNbO3 samples of 1.0mm thickness.
基金Supported by the National Natural Science Foundation of China,and the National Climbing Programme of Fundamental Research。
文摘A new method to suppress the fanning noise caused by He-Ne laser in the cooperation with Ar+laser in photorefractive LiNbO_(3):Fe crystal was successfully realized.This method is simple and efficient.By using this method,fanning-noise-free hologram can be stored in LiNbO_(3):Fecrystal.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60978020,61178004Research Fund for the Doctoral Program of Higher Education of China(20110031120005)+1 种基金Program for Changjiang Scholars and Innovative Research Team in Nankai Universitythe Fundamental Research Funds for the Central Universities.
文摘Beam manipulation by metallic nanoslit arrays with perpendicular cuts inside the slits was investigated numerically.The simulated results performed by the finite element method(FEM)show that perpendicular cuts with different heights can modulate phase retardation of the transmitted light through the slits.With the proper distribution of cut height,a focused beam is achieved in our metallic nanostructure with four-time amplitude at the focus point and half focal length compared to a slit array without cuts inside.By using asymmetric distribution of height amplitude,a beam deflection around 6°can also be realized in our design.
基金Supported by the Special Funding for the Excellent Young Researchers under Grant No.69825108the National Natural Science Foundation of China under Grant No.69678108,and the“973”Project under Grant No.G1999033004.
文摘The steady intensity of a forward phase conjugate wave (FPCW) is successfully observed along the c-axis in the highly magnesium-doped lithium niobate crystal. We put forward a detailed physical picture for our experiment phenomena. The FPCW is generated from the phase-mismatch in a three-wave coupling process, and tends to be stable accompanied with the building of photorefractive gratings and four-wave coupling processes. Our experimental result is also discussed and analysed by means of the wave coupling theory, and the theoretical expression is provided for the experiment.
基金Supported by the Special Funds for Excellent Young Researchers from the National Natural Science Foundation of China under Grant Nos.69825108 and 19734040the National Education Ministry of China,and“973”project(Grant G1999033003).
文摘Light-induced absorption in the nominally pure bismuth silicon oxide is investigated experimentally and the result shows that it consists of transient and persistent parts. The experimental evidence is analysed based on the model of three groups of trap (donor) centres.
