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991.
992.
High-power operation of diode-pumped fiber lasers at wavelength near 2μm are demonstrated with short length of heavily Tm3 -doped silica glass fibers. With 7-cm long fiber, a laser at near 2 μm is obtained with the threshold of 135 mW, maximum output power of 1.09 W, and slope efficiency of 9.6% with respect to the launched power from a laser diode at 790 nm. The output stability of this fiber laser is within 5%.The dependence of the performance of fiber lasers on the operation temperature and cavity configuration parameters is also investigated. 相似文献
993.
The growth parameters affecting the deposition of self-assembled InAs quantum dots (QDs) on GaAs substrate by low-pressure metal-organic chemical vapor deposition (MOCVD) are reported. The low-density InAs QDs (- 5 × 10^8cm^-2) are achieved using high growth temperature and low InAs coverage. Photoluminescence (PL) measurements show the good optical quality of low-density QDs. At room temperature, the ground state peak wavelength of PL spectrum and full-width at half-maximum (FWHM) are 1361 nm and 23 meV (35 nm), respectively, which are obtained as the GaAs capping layer grown using triethylgallium (TEG) and tertiallybutylarsine (TBA). The PL spectra exhibit three emission peaks at 1361, 1280, and 1204 nm, which correspond to the ground state, the first excited state, and the second excited state of the ODs, respectively. 相似文献
994.
995.
研究了Mn-898wt%Sb合金在无磁场以及磁场为B=88 T、不同强度的磁场梯度作用下的凝固组织变化,并分析了上述不同强磁场条件对合金凝固组织影响的作用机理.研究表明,在较大梯度磁场作用时,试样中出现了初生MnSb相与Sb相以及共晶组织共存的现象,而且初生MnSb相与Sb相产生了明显的分层现象.此外,磁场梯度作用下初生MnSb相和Sb相的含量随着磁场梯度的增大而增加.论文对初生MnSb相和Sb相的分离机理进行了探讨,发现在梯度磁场作用下,熔融金属中不同磁化率的合金组元团簇受力不同,造成 相似文献
996.
997.
998.
Chunling Liu Yanping Yao Chunwu Wang Xin Gao Zhongliang Qiao Mei Li Yuxia Wang Baoxue Bo 《中国光学快报(英文版)》2008,6(3)
In order to improve the optical properties of the Ⅲ-Ⅴ laser diodes(LDs) by means of H2S plasma passivation technology,H2S plasma passivation treatment is performed on the GaAs(110) surface.The optimum passivation conditions obtained are 60-W radio frequency(RF)power and 20-min duration.So the laser cavity surfaces axe treated under the optimum passivation conditions.Consequently,compared with unpassivated lasers with only AR/HR-coatings,the catastrophic optical damage (COD) threshold value of the passivated lasers by H2S plasma treatment is increased by 33%,which is almost the same as that of (NH4)2Sx treatment.And the life-test experiment has demonstrated that this passivation method is more stable than(NH4)2Sx solution wet-passivated treatment. 相似文献
999.
Kinetic modeling of a high power fast-axial-flow CO2 laser with computational fluid dynamics method 总被引:1,自引:0,他引:1
A new computational fluid dynamics (CFD) method for the simulation of fast-axial-flow CO2 laser is developed.The model which is solved by CFD software uses a set of dynamic differential equations to describe the dynamic process in one discharge tube.The velocity,temperature,pressure and turbulence energy distributions in discharge passage are presented.There is a good agreement between the theoretical prediction and the experimental results.This result indicates that the parameters of the laser have significant effect on the flow distribution in the discharge passage.It is helpful to optimize the output of high power CO2 laser by mastering its kinetic characteristics. 相似文献
1000.
ShiLing Li 《中国科学G辑(英文版)》2008,51(10):1479-1488
The formation of optical planar waveguides in LiNbO3 and stoichiometric LiNbO3 crystals by proton exchange was reported. The prism-coupling method was used to characterize the dark-line spectroscopy at
the wavelength of 633 and 1539 nm, respectively. The mode optical near-field outputs from proton-exchanged LiNbO3 and SLN waveguides at 633 nm were presented. The mode field from stoichiometric LiNbO3 (SLN) waveguide is lighter and more uniform than that from LiNbO3 waveguide, which means the quality of the waveguide in SLN crystal is better than that of the LiNbO3 waveguide. For proton-exchanged LiNbO3 waveguides, the evolution of the refractive index profile with annealing was presented. The disorder profiles of Nb atoms
in proton-exchanged LiNbO3 waveguides were obtained by Rutherford backscattering/channeling technique. It is shown that the longer the exchange time,
the larger the displacement of Nb atoms.
Supported by the National Natural Science Foundation of China (Grant No. 10475052) and the Scientific Research Start-up Financing
of Qufu Normal University 相似文献