Broadband continuum generation in an irregularly multicore microstructured optical fiber

A broadband continuum generation is reported in a novel multicore microstructured optical fiber (MOF) where irregular air holes are randomly distributed in cladding. By launching ultrashort light pulses from a Ti:sapphire laser into a 190-mm-long fiber of this type, we have observed a group of continua generated from different cores, each with distinct color. 20-dB bandwidth of the broadest continuum is 1260 nm with an average power of 143 mW. The result confirms that the multicore MOF can be fabricated, with different dispersion profiles tailored for specific supercontinuum (SC) generation towards practical applications.     

Measurement of the argon-gas-induced broadening and line shifting of the barium Rydberg level 6s24d 1D2 by two-photon resonant nondegenerate four-wave mixing

We apply two-photon resonant nondegenerate four-wave mixing with a resonant intermediate state to the obser-vation of the broadening and shifting of the barium Rydberg level 6s24d 1^D2 by collision with argon. The collision broadening and shifting cross sections are measured. This technique is purely optical, and can investigate the pressure dependence of the transverse relaxation rate-P21 between the Rydberg state and an intermediate state, as well as the transverse relaxation rate F20 between the Rydberg state and the ground state.     

Measurement of the argon-gas-induced broadening and line shifting of the barium Rydberg level 6s24d ¹D₂ by two-photon resonant nondegenerate four-wave mixing

We apply two-photon resonant nondegenerate four-wave mixing with a resonant intermediate state to the observation of the broadening and shifting of the barium Rydberg level 6s24d 1D2 by collision with argon.The collision broadening and shifting cross sections are measured.This technique is purely optical,and can investigate the pressure dependence of the transverse relaxation rate Γ21 between the Rydberg state and an intermediate state,as well as the transverse relaxation rate Γ20 between the Rydberg state and the ground state.     

Three-Photon Resonant Nondegenerate Six-Wave Mixing in a Dressed Atomic System

We report a three-photon resonant nondegenerate six-wave mixing （NSWM） in a dressed cascade five-level system. It has advantages that phase match condition is not stringent and NSWM signal is enhanced tremendously due to the multiple resonance with the atomic transition frequencies. In the presence of a strong coupling field, the threephoton resonant NSWM spectrum exhibits＂ Autler-Townes splitting. This technique provides a spectroscopic tool for measuring not only the resonant frequency and dephasing rate but also the transition dipole moment between two highly excited atomic states.     

BaIn6Y2O13∶Yb3+, Er3+的制备及上转换发光性质的研究

采用高温固相法合成了不同Yb3+和Er3+掺杂浓度的BaIn₆Y₂O₁₃上转换发光材料。XRD数据显示,所合成的BaIn₆Y₂O₁₃∶Yb3+, Er3+属于六方晶系,引入激活剂并没有改变基质的晶体结构。利用971 nm半导体激光器激发样品,测量样品在不同激发光密度下上转换发射光谱和发射光功率,计算了上转换能量效率。数据表明在激发密度不变,激活剂浓度增加时,上转换光绿红比减小;激活剂浓度不变激发光密度增加时,发射光绿红比增大。分析表明是由于Er3+之间的交叉弛豫增强导致绿红比随激活剂掺杂浓度的增加而减小;Yb3+和Er3+之间的能量传递和Er3+的激发态吸收增强导致绿红比随激发密度的增加而增大。随着激发功率增加, 在较低激发功率时, 上转换绿光发射强度与激发功率的二次方成正比; 在较高激发功率时, 上转换绿光发射强度与激发功率的一次方成正比, 与报道的结果一致。能量效率存在极大值, 分别为0.38%(Yb3+掺杂浓度3%, Er3+掺杂浓度1%)和0.06%(Yb3+掺杂浓度9%, Er3+掺杂浓度3%), 产生极值的一个原因是4I_13/2亚稳态能级寿命较长, 聚集了大量电子, 使基态电子急剧减少, 导致上转换泵浦效率降低。     

双光子共振非简并四波混频测量Ba原子里德伯态的碰撞展宽和频移

采用双光子共振非简并四波混频测量了Ar缓冲气压引起的Ba原子里德伯6snd ¹D₂谱线系的碰撞展宽和频移, 计算了n=16---33的碰撞展宽截面和频移截面. 本方法是一种纯光学的测量技术, 当采用窄带激光器时可以获得里德伯态的消多普勒光谱. 与传统实验方法测量到的里德伯态纵向弛豫的碰撞展宽不同, 本方法可以研究碰撞引起的两能态间横向弛豫的展宽.     

窄线宽高效率的全光纤Yb~(3+)激光器

利用光纤布拉格光栅 (FBG)作为腔镜 ,研制了一种全光纤结构的掺 Yb3+ 光纤激光器。以泵浦波长978nm的 L D作为抽运源 ,在 10 6 0 .4 nm波段获得了 0 .14 nm的窄线宽激光输出。实验中发现掺 Yb3+光纤长度对激光器的阈值及输出功率均有影响 ,但光纤激光器的输出线宽保持不变。最大激光输出功率为 2 .36 m W,斜率效率达到 2 2 .2 %。     

8.6W掺Yb3+双包层光纤激光器的研究

采用多模大功率半导体激光器泵浦掺Yb双包层D型光纤,详细研究了输出功率与泵浦功率的关系,获得了1.09μm,功率为8.6W的激光输出.     

封离型CO_2激光器的技术和应用

性能的改进，成本的下降，加之可靠性和耐用性的提高，使封离型CO2激光器对于工业应用极具吸引力。在过去的十年间，就激光器的销售情况和应用种类来看，封离型CO2激光器市场有了显著的增长。初期，激光输出功率在10W和25W；这期间的市场增长是由于激光器价格的低廉。因广泛地适用于非金属材料的切割和雕刻，这种低功率激光器已经在许多台式激光制造系统里找到了用武之地，例如美国Universal激光系统和Epilog激光系统。当输出功率提高以后，这种激光可用来切割金属、陶瓷、厚的聚丙烯塑料和木料，切割速度可达每分钟几百英尺。如今，封…