A high energy, high beam quality short-pulse diode-pumped Nd:YAG master oscillator power-amplifier (MOPA) laser with two amplifier stages is demonstrated. The two-rod birefringence compensation was used as beam quality controlling methods, which presents a short-pulse energy of 40 mJ with a beam quality value of M-2 = 1.2 at a repetition rate of 400Hz. The MOPA system delivers a short-pulse energy of 712.5 mJ with a pulse width of 12.4 ns. The method of spherical aberration compensation is improved the beam quality, a M-2 factor of 2.3 and an optical-to-optical efficiency of 27.7% is obtained at the maximum laser out power. The laser obtained 1.4J out energy with polarization integration.

An average 9 kilowatt-level direct-D2O-cooled side-pumped Nd:YAG multi-disk laser resonator at QCW mode with a pulse width of 250μs is presented, in which the straight-through geometry is adopted the oscillating laser propagates through 40 Nd:YAG thin disks and multiple cooling D2O flow layers in the Brewster angle. Much attention has been paid on the design of the gain module, including an analysis of the loss of the laser resonator and the design of the Nd:YAG thin disk. Experimentally, laser output with the highest pulse energy of more than 20 J is obtained at a repetition frequency of 10 Hz. At high repetition frequency, the average output power 9.8 kW with ηo-o = 26% and 9.1 kW with ηo-o = 21.8% are achieved in the stable resonator and unstable resonator, respectively, and in the corresponding beam quality factor βstable= 14.7 and βunstable= 9.5 respectively. To the best of our knowledge, this is the first demonstration of a 9 kilowatt-level direct-liquid-cooled Nd:YAG thin disk laser resonator.

A high energy,high beam quality short-pulse diode-pumped Nd:YAG master oscillator power-amplifier (MO-PA)laser with two amplifier stages is demonstrated.The two-rod birefringence compensation is used as beam quality control measure,which presents a short-pulse energy of 40 mJ with a beam quality value of M2=1.2 at a repetition rate of 400 Hz.The MOPA system delivers a short-pulse energy of 712.5 mJ with a pulse width of 12.4 ns.The method of spherical aberration com-pensation has improved the beam quality,a M2factor of 2.3 and an optical-to-optical efficiency of 27.7% are obtained at the max-imum laser out power.The laser has obtained 1.4 J output energy with polarization integration.

A novel high-power direct-liquid-cooled thin-disk solid-state laser is designed, in which the distributed gain system is composed of tens or hundreds transmission disks by intensive stacking. A special kind of laser cooling liquid flows in the planar micro-channels between gain media, and thus the direct cooling of disks is realized. The thermal stress, the reflective surface deformation and so on caused by the soldering between gain media and the heat-sink in the traditional high power solid-state laser arc successfully avoided. In addition, the parameters such as intra-cavity loss and aberration arc optimized. The key factors influencing the optical-to-optical conversion efficiency arc analyzed, and the methods for controlling laser beam quality arc introduced according to the thermal aberration characteristics. A gain module is composed of 20 disks by intensive stacking with a special angle. With these gain modules, a quasi-continuous-wave (QCW) polarized laser with an output power of larger than 9 kW is obtained in both stable and unstable cavities. Moreover, the whole volume of this laser source in laboratory is smaller than 0.1 m(3).

A high power multi-pass diode-pumped solid-state MOPA system with large core diameter tapered quartz fiber as phase conjugator is experimentally investigated. The results of the effects of laser longitudinal mode characteristic, laser pulse width and fiber surface optical quality on SBS reflectivity are presented. Maximum SBS reflectivity of 69.7% is obtained with the repetition rate of 1000 Hz, input pulse energy of 38mJ and pulse width of 24 ns. The phase conjugator is made from a taper shaped quartz fiber with the diameter of 1mm at the input end and 0.4mm at the other end. It has good application prospects in improving the beam quality and compressing the pulse width for high power laser system with high repetition rate.

A large aperture tapered fused silica fiber phase conjugate mirror with a maximum 50.7% stimulated Brillouin scattering (SBS) reflectivity is presented, which is operated with 400Hz pulse repetition rate and 36.5mJ input pulse energy. To the best of our knowledge, it is the first time that over 50% SBS reflectivity is achieved by using solid-state phase conjugate mirror under such high pulse repetition rate and high pulse energy. With much higher pulse repetition rate of 500 and 1000Hz, the maximum SBS reflectivity is 41.2% and 33.3%, respectively. A single-longitudinal-mode Nd:YAG laser is experimentally studied with master oscillator power amplifier (MOPA) scheme using such a tapered fiber as a phase conjugate mirror. A 101mJ pulse energy is achieved at 400Hz repetition rate, with a pulse width of 6ns and a M2 factor of less than 2. The corresponding peak power reaches 16.8MW.

在1000 Hz高重复频率条件下,对单一大口径锥度光纤相位共轭镜(PCM)进行了详细的实验研究.对采用普通红宝石切割刀和进口LDC-200光纤切割刀切割的锥度光纤受激布里渊散射(SBS)反射率进行了比较,结果表明光纤表面切割好坏对反射率提升具有重要的影响.在两种抽运脉宽24 ns和15 ns下,对均由LDC-200光纤切割刀切割的锥度光纤SBS反射率进行了比较,在同样注入近40 mJ时,分别得到最高70%和50%的反射率.对抽运脉冲宽度为15 ns时,应用该锥度光纤PCM的双通输出激光能量、脉冲宽度、光束质量变化情况进行了测量,得到42 mJ,脉宽约1.5 ns的双通输出,光束质量得到明显改善.

对光纤中受激布里渊散射(SBS)的耦合波方程进行了合理的近似和简化,在瞬态SBS过程的耦合波方程的基础上,构建了数值计算的模型.特别是对变芯径锥度光纤中的SBS耦合波方程进行数值求解,得到了受激散射过程中抽运光和斯托克斯光的功率在传播过程中的变化规律,并比较了光纤参数对SBS的影响,优化了锥度光纤作为高功率高重复频率激光二极管抽运固体激光器中的相位共轭镜应用中的参数,为其在改善光束质量中的应用提供了系统的参数优化规律.此外,将模拟数据与实验数据进行对比,验证了模型的合理性.

使用重复频率为400 Hz的Nd∶YAG单纵模主振荡器功率放大（MOPA）激光器作为光源,大口径锥度光纤作为受激布里渊散射（SBS）种子池产生SBS种子光,固体熔石英棒作为SBS放大池,对反向注入的SBS种子光在熔石英棒中呈现不同增益,也即不同抽运功率条件下的布里渊放大行为从功率、时间和空间三个大的方面进行了详细的实验研究,包括放大的SBS输出功率、注入SBS种子光放大倍率、总的SBS反射率、熔石英棒布里渊放大器提取效率以及脉冲宽度和光束质量随SBS种子注入功率的变化情况等。获得了最高输出15.5 W的放大SBS输出、70倍的SBS种子光放大倍率、大于50%的总反射率以及52%的能量提取效率;观察到脉冲展宽以及布里渊放大器中的增益导引两种现象。实验结果表明,在小信号SBS种子光和大信号SBS种子光注入情况下,熔石英棒布里渊放大器具有不同的放大特性。另外,在实验过程中还发现,SBS种子光和抽运光的空间重合程度以及熔石英棒中抽运功率密度的大小是影响SBS放大输出功率的两个重要方面。

使用最高重复频率可达1000 Hz的脉冲激光二极管抽运的电光调Q单纵模激光器作为种子源,经过两级预放大器和两级主功率放大器后获得高重复频率高能量的激光输出.然后使用此光源对由芯径为1 mm和400 μm的石英光纤组合而成的大口径锥度光纤固体相位共轭镜在重复频率分别为1000,500和400 Hz情况下的受激布里渊散射反射率进行了详细的实验研究,并分别得到33.3%,41.2%和50.7%的最高反射率.实现了固体相位共轭镜在高重复频率大能量条件下大于50%的受激布里渊散射反射率.在重复频率为400 Hz时,激光脉冲宽度从24 ns压缩到6 ns,压缩比为4:1,且脉冲光滑无调制.

L-selectin is a member of the selectin family that play an important role both in mediating the initial capture and subsequent rolling of leukocytes along the endothelial cells. Furthermore, L-selectin can function as a signal molecule. In our previous studies, we reported that L-selectin ligation could regulate CSF-1 (colony-stimulating factor-1) gene transcription, in which AP-1 acts as a crucial transcriptional factor. Here we investigated the function of the NFAT in the CSF-1 gene transcriptional events. We found that overexpression of WT NFAT induce CSF-1 gene transcription greatly in the activated Jurkat cells. Furthermore, we found that NFAT can be recruited to the nucleus after L-selectin ligation, and the nuclear NFAT interacts with the CSF-1 promoter region to regulate CSF-1 gene transcription in the L-selectin ligation activated Jurkat cells. These results indicate that nuclear NFAT can activate CSF-1 gene transcription by connecting with the CSF-1 promoter in the signaling events induced by L-selectin ligation.

使用脉冲激光二极管抽运的单纵模激光器作为种子源,通过两级预放大器和两级主放大器的单通放大,得到重复频率400 Hz,单脉冲能量36.5 mJ,脉宽24 ns的单纵模激光输出,且输出光束质量为M2x=1.78,M2y=2.13。应用大口径锥度融石英光纤作为相位共轭镜,获得了大于50%的受激布里渊散射反射率,入射激光被压缩到6 ns左右,大幅提升了脉冲峰值功率;由于相位共轭特性,反射回的激光将沿原路返回再次通过主放大器,补偿了激光晶体中的相位畸变,并再次提取晶体中的能量进行有效放大。双通后输出重复频率400 Hz,单脉冲能量101.25 mJ,脉冲宽度6 ns左右的单纵模激光,峰值功率可高达16.8 MW,光束质量因子为M2x=1.74,M2y=1.93。可见,在应用该相位共轭镜双通过后,光束质量并没有继续恶化,而是有所提升;使用平面镜双通后的光束质量因子M2≈4,从而有效证实了该光纤相位共轭镜补偿畸变的作用。

Preliminary influence factor analysis of beam quality of high-average-power and high-beam-quality intracavity frequency doubled green laser is presented. The methods of improving beam quality such as optimal design of resonator cavity and compensation of thermal effects are described. The corresponding experimental research is done. With the control of beam quality, the green laser power of 63.7 W is obtained in a 8 mm×8 mm×12 mm KTP crystal with an M2 value of 9.65 and an optical-to-optical conversion efficiency of 9.7% at a pulse repetition rate of 10 kHz, and the green laser power of 79 W is generated in a 8 mm×8 mm×30 mm LBO crystal with an M2 value of 6.46 and an optical-to-optical conversion efficiency of 9.8% at a pulse repetition rate of 15 kHz.

Integrin regulation in neutrophil adhesion is essential for innate immune response. c-Abl kinase is a nonreceptor tyrosine kinase and is critical for signaling transduction from various receptors in leukocytes. Using neutrophils find dHL-60 (neutrophil-like differentiation of HL-60) cells, we show that c-Abl kinase is activated by beta(2) integrin engagement and is required for beta(2) integrin-dependent neutrophil sustained adhesion and spreading. The expression of beta(2) integrin on neutrophils induced by TNF-alpha is not affected by c-Abl kinase inhibitor STI571, suggesting that c-Abl kinase is not involved in TNF-alpha-induced integrin activation. The recruitment of c-Abl kinase to beta(2) integrin is dependent on talin head domain, which constitutively interacts with beta(2) integrin cytoplasmic domain. After activated, c-Abl kinase increases the tyrosine phosphorylation of Vav. The SH3 domain of c-Ahl kinase is involved in its interaction with talin and Vav. Thus, c-Abl kinase plays an essential role in the activation of Vav induced by beta(2), integrin ligation and in regulating neutrophil-sustained adhesion and spreading. The Journal of Immunology, 2009, 182: 3233-3242.

Skeletal muscle regeneration is a highly orchestrated process initiated by activation of adult muscle satellite cells. Upon muscle injury, the inflammatory process is always accompanied by muscle regeneration. Leukotriene B 4 is one of the essential inflammatory mediators. We isolated and cultured primary satellite cells. RT-PCR showed that myoblasts expressed mRNA for LTB 4 receptors BLT1 and BLT2, and LTB4 promoted myoblast proliferation and fusion. Quantitative real-time PCR and immunoblotting showed that LTB 4 treatment expedited the expression process of differentiation markers MyoD and M-cadherin. U-75302, a specific BLT1 inhibitor, but not LY2552833, a specific BLT2 inhibitor, blocked proliferation and differentiation of myoblasts induced by LTB 4 , which implies the involvement of the BLT1 pathway. Overall, the data suggest that LTB 4 contributes to muscle regeneration by accelerating proliferation and differentiation of satellite cells.

Integrin regulation in neutrophil adhesion is essential for innate immune response. c-Abl kinase is a nonreceptor tyrosine kinase and is critical for signaling transduction from various receptors in leukocytes. Using neutrophils and dHL-60 (neutrophil-like differentiation of HL-60) cells, we show that c-Abl kinase is activated by β2 integrin engagement and is required for β2 integrin-dependent neutrophil sustained adhesion and spreading. The expression of β2 integrin on neutrophils induced by TNF-α is not affected by c-Abl kinase inhibitor STI571, suggesting that c-Abl kinase is not involved in TNF-α-induced integrin activation. The recruitment of c-Abl kinase to β2 integrin is dependent on talin head domain, which constitutively interacts with β2 integrin cytoplasmic domain. After activated, c-Abl kinase increases the tyrosine phosphorylation of Vav. The SH3 domain of c-Abl kinase is involved in its interaction with talin and Vav. Thus, c-Abl kinase plays an essential role in the activation of Vav induced by β2 integrin ligation and in regulating neutrophil-sustained adhesion and spreading.

Recruitment of leukocytes onto inflamed tissues is an important physiological event, in which L-selectin plays an essential role in initial leukocyte capture and at the same time, triggers cell signaling. Lck is a member of the Src family of protein tyrosine kinases and is critical for T cell activation triggered by receptor ligation. Here, we demonstrated that Lck was associated directly with and phosphorylated the L-selectin cytoplasmic tail upon L-selectin engagement with sulfatides. Through the direct interaction with ZAP-70 and c-Abl via its Src homology 2 (SH2) and SH3 domains, Lck organized a signaling complex at the cytoplasmic tail of L-selectin. In the cells with Lck knockdown by small interfering RNA treatment, L-selectin signaling was suppressed dramatically, as indicated by reduced phosphorylation of c-Abl and ZAP-70. Re-expression of wild-type or constitutively active but not kinase-dead murine Lck rescued the phosphorylation completely, but the SH2 domain mutant or the SH3/SH2 double mutant of murine Lck had no effect. These results suggest that Lck plays a critical role in L-selectin signaling upon sulfatides stimulation.

L-selectin is a cell adhesion molecule that plays an important role both in mediating the initial capture and subsequent rolling of leukocytes along the endothelial cells and in the signal transduction for leukocyte activation. In our previous studies, we reported that L-selectin ligation could increase macrophage colony-stimulating factor (CSF)-1 gene transcription, in which c-Abl acts as a crucial cytoplasmic kinase. Here we investigated the function of the nuclear c-Abl kinase in the CSF-1 gene transcriptional events triggered by L-selectin ligation. We determined that c-Abl kinase recruits to the nucleus following L-selectin ligation, and the nuclear c-Abl kinase can phosphorylate c-Jun and regulate activator protein (AP)-1 activity. Furthermore, the activated c-Abl kinase interacts with AP-1 and forms a complex in the CSF-1 promoter region to regulate CSF-1 gene transcription in the L-selectin ligation-activated cells. These results indicate that nuclear c-Abl kinase can activate CSF-1 gene transcription by regulating AP-1 activity in the signaling events induced by L-selectin ligation.

Lymphocyte recruitment onto inflamed tissues requires cells tethering to and rolling on vascular surfaces under flow. L‐selectin is constitutively expressed on leukocytes to mediate the leukocytes’ initial capture and subsequent rolling along the vessel. Apart from its adhesive function, engagement of L‐selectin also results in cell activation, which is related to the completed signaling transduction. Here we show that ligation of L‐selectin with its mAb increases c‐Abl kinase activity, and that the activated c‐Abl kinase can be recruited to and phosphorylate the cytoplasmic domain of L‐selectin. In addition, the activated c‐Abl kinase can regulate Zap70 kinase by increasing the phosphorylation of the Y319 site of Zap70 kinase and connect with Zap70 kinase through its SH2 domain. These results indicate that c‐Abl kinase plays an important role in accepting and transferring the upstream activation events induced by L‐selectin ligation.

The application prospect and production methods of the high-repetition-rate, high average power 2 μm laser were reported. With the KTP crystal refractive index ellipse and the Sellmeier equations, the tuning characteristic of the crystal about the cutting angle was analyzed when the 1.064 μm continuous Nd:YAG laser pumped the type II phase matching KTP crystal. The cutting angle tuning curve was also calculated. As a result, when the cutting angle was 52.6°, the signal and the idler were degenerated at 2.128 μm with perpendicular polarization. To restrain the dispersion effect, the authors combined the intracavity optical parametric oscillator (OPO) with the short crystals connecting external OPO and designed an experimental set of intracavity doubly resonant optical parametric oscillator with two short KTP crystals connecting, with which high-repetition-rate 2 μm laser output was readized with acoustic-optic Q-switch. Finally, the threshold, the converting efficiency, the crystal dispersion length and the linewidth were numerically simulated.