The effects of a Mg^2＋ ion on the dopant occupancy and upconversion luminescence of a Ho^3＋ ion in LiNbO3 crystal are reported. The birefringence gradient of the crystal is measured to investigate the optical homoge...The effects of a Mg^2＋ ion on the dopant occupancy and upconversion luminescence of a Ho^3＋ ion in LiNbO3 crystal are reported. The birefringence gradient of the crystal is measured to investigate the optical homogeneity. The X-ray powder diffraction spectrum and the upconversion luminescence are used to investigate defect structure and spectroscopic properties of Mg,Ho：LiNbO3. Under 808-nm excitation, blue, red, and very intense yellow-green bands are observed. Based on the energy levels of Ho^3＋ in LiNbO3, and the pump intensity dependence of the observed emission, an excitation scheme is presented. The upconversion emission spectra reveal an enhancement of upconversion intensity when the Mg^2＋ ions are introduced into Ho：LiNbO3. The main upconversion mechanism is discussed in this work.展开更多
This paper investigates the properties of thickness extension mode excited by lateral electric field on LiNbO3 by using the extended Christoffel-Bechmann method. It finds that the lateral field excitation coupling fac...This paper investigates the properties of thickness extension mode excited by lateral electric field on LiNbO3 by using the extended Christoffel-Bechmann method. It finds that the lateral field excitation coupling factor for amode （quasi-extensional mode） reaches its maximum value of 28% on Xmcut LiNbO3. The characteristics of a lateral field excitation device made of X-cut LiNbO3 have been investigated and the lateral field excitation device is used for the design of a high frequency ultrasonic transducer. The time and frequency domain pulse/echo response of the LiNbO3 lateral field excitation ultrasonic transducer is analysed with the modified Krimholtz-Leedom-Matthae model and tested using traditional pulse/echo method. A LiNbO3 lateral field excitation ultrasonic transducer with the centre frequency of 33.44 MHz and the -6 dB bandwidth of 33.8% is acquired, which is in good agreement with the results of the Krimholtz-Leedom-Matthae model. Further analysis suggests that the LiNbO3 lateral field excitation device has great potential in the design of broadband high frequency ultrasonic transducers.展开更多
in this paper, unilateral fin line configuration is considered as a new type of lithium niobate (LiNb03) optical waveguide modulator. Base on the spectral domain method and the spectral do- main immittance approach, ...in this paper, unilateral fin line configuration is considered as a new type of lithium niobate (LiNb03) optical waveguide modulator. Base on the spectral domain method and the spectral do- main immittance approach, the concrete method to caculate the unilateral fin line on the substrate of anisotropic LiNb03 Crystal is put frond. The caculation of the dispersion and characteristic impedance of the fin line on the substrate of Z-cut LiNb03 crystal in 3 centimeters waveband shows that this configuration is practical. If the crystal is made smaller and thiner, a modulator at higher wave band may well be realized.展开更多
基金supported by the China Postdoctoral Science Foundation (Grant No. 2012M520759 )the Science and Technology Research Project of Education Bureau of Heilongjiang Province, China (Grant No. 12531098)
文摘The effects of a Mg^2＋ ion on the dopant occupancy and upconversion luminescence of a Ho^3＋ ion in LiNbO3 crystal are reported. The birefringence gradient of the crystal is measured to investigate the optical homogeneity. The X-ray powder diffraction spectrum and the upconversion luminescence are used to investigate defect structure and spectroscopic properties of Mg,Ho：LiNbO3. Under 808-nm excitation, blue, red, and very intense yellow-green bands are observed. Based on the energy levels of Ho^3＋ in LiNbO3, and the pump intensity dependence of the observed emission, an excitation scheme is presented. The upconversion emission spectra reveal an enhancement of upconversion intensity when the Mg^2＋ ions are introduced into Ho：LiNbO3. The main upconversion mechanism is discussed in this work.
基金supported by the National Natural Science Foundation of China (Grant No.60571014)Shenzhen Shuangbai Project
文摘This paper investigates the properties of thickness extension mode excited by lateral electric field on LiNbO3 by using the extended Christoffel-Bechmann method. It finds that the lateral field excitation coupling factor for amode （quasi-extensional mode） reaches its maximum value of 28% on Xmcut LiNbO3. The characteristics of a lateral field excitation device made of X-cut LiNbO3 have been investigated and the lateral field excitation device is used for the design of a high frequency ultrasonic transducer. The time and frequency domain pulse/echo response of the LiNbO3 lateral field excitation ultrasonic transducer is analysed with the modified Krimholtz-Leedom-Matthae model and tested using traditional pulse/echo method. A LiNbO3 lateral field excitation ultrasonic transducer with the centre frequency of 33.44 MHz and the -6 dB bandwidth of 33.8% is acquired, which is in good agreement with the results of the Krimholtz-Leedom-Matthae model. Further analysis suggests that the LiNbO3 lateral field excitation device has great potential in the design of broadband high frequency ultrasonic transducers.
基金the Ministry of Posts and Telecommunications P. R. China
文摘in this paper, unilateral fin line configuration is considered as a new type of lithium niobate (LiNb03) optical waveguide modulator. Base on the spectral domain method and the spectral do- main immittance approach, the concrete method to caculate the unilateral fin line on the substrate of anisotropic LiNb03 Crystal is put frond. The caculation of the dispersion and characteristic impedance of the fin line on the substrate of Z-cut LiNb03 crystal in 3 centimeters waveband shows that this configuration is practical. If the crystal is made smaller and thiner, a modulator at higher wave band may well be realized.
