开放的V型三能级系统中原子注入和退出速率对位相相关的无反转激光增益和强度空间演化的调制作用

利用数值计算结果, 研究了具有自发辐射诱导相干的开放V 型三能级原子系统中的传播效应. 研究表明: 改变探测场和驱动场之间的相对位相对无反转激光(LWI)增益和 强度随传播距离的变化即空间演化具有重要的影响; 而原子的注入速率比(S)和退出速率(r₀)的改变将对位相相关的LWI增益和强度的空间演化产生明显的调制作用. 在S(r₀)的一定取值范围内, S(r₀)的值越大, LWI增益和强度越大且强度达到极大值需要的传播距离越长; 相应封闭系统中LWI增益和强度的最大值及能产生增益的传播距离都小于开放系统. Doppler效应对LWI增益和强度的空间演化也具有明显的影响, 存在Doppler效应时得到的LWI增益和强度明显小于无Doppler效应时的值.     

Osp(1,2)自旋链的潜藏定域规范不变性

在量子反散射框架内研究了Osp（1，2）自旋链的潜藏定域规范不变性．结果表明，该模型允许AbelU（1）规范变换，其能谱在规范变换下保持不变，而本征矢及Bethe ansatz方程明显与规范变换相关． 关键词：     

辫子群的全部二维不可约表示

通过直接解矩阵方程给出了Bn群的全部二维不可约表示．     

XYZ自旋开链的Lax及其边界K矩阵

明显构造了开边界条件下ＸＹＺ模型的Ｌａｘ对，进而得到了其一般边界Ｋ矩阵。     

辫子群的双参数不可约表示

在广义的Conway条件下,引入双参数完备算符集,借助杨图,给出了B_n群的双参数不可约表示。     

Effect of Doppler broadening on gain in an open V-type inversionless lasing system

Our study shows that for the copropagating probing and driving fields, the gain without inversion doesn't monotonously decrease or increase with the increasement of Doppler width. When the driving field is resonant, at a suitable Doppler width, we can get a maximum value of the gain without inversion, which is much larger than that obtained when Doppler broadening is absent.     

Population transfer by femtosecond laser pulses in a ladder-type atomic system

The population transfer in a ladder-type atomic system driven by linearly polarized sech-shape femtosecond laser pulses is investigated by numerically solving Schr6dinger equation without including the rotating wave approximation （RWA）. It is shown that population transfer is mainly determined by the Rabi frequency （strength） of the driving laser field and the chirp rate, and that the ratio of the dipole moments and the pulse width also have a prominent effect on the population transfer. By choosing appropriate values of the above parameters, complete population transfer can be realized.     

Inversionless gain enhancing due to Doppler broadening in a closed lambda-type system

An analysis is made of the effect of Doppler broadening on gain without inversion （GWI） from different aspects in a closed lambda-type three-level system with an incoherent pump. It is shown that, regardless of the driving field being on resonance or not, for the counter- or co-propagating of the probe and driving fields （PDF）, GWI does not monotonically decrease or increase with increasing Doppler width. Except for the case of counter-propagating PDF with off-resonance driving field, at a suitable Doppler width one can obtain a gain maximum value much larger than that without Doppler broadening; especially in the situation of the resonant driving field, the co-propagating geometry leads to a larger GWI. In addition, for the counter-propagating geometry, when Doppler width is larger enough, GWI oscillation occurs, and the oscillation amplitude and region increase with increasing Doppler width. These conclusions are very different from that obtained in previous investigation （Lukin et al, Laser Phys. 6 436 （1996））.     

84Rb的高自族态研究

利用75MeV的¹⁸O束流,通过⁷⁰Zn(¹⁸O,p3n)反应布居了⁸⁴Rb核的高自旋态,测量了激发函数,γ–γ符合及DCO比值,新观察到了40个能级,50多条γ跃迁,建立了到目前为止最完整的能级纲图,其正负宇称分别推高到了17⁺和17^－.通过与Rb各奇–奇同位素核和N=47的各奇–奇核比较,发现它们的结构非常相似.     

~(84)Rb的高自族态研究

利用75MeV的18O束流，通过70Zn（18O，p3n）反应布居了84Rb核的高自旋态，测量了激发函数，γ－γ符合及DCO比值，新观察到了40个能级，50多条γ跃迁，建立了到目前为止最完整的能级纲图，其正负宇称分别推高到了17+和17-．通过与Rb各奇-奇同位素核和N＝47的各奇-奇核比较，发现它们的结构非常相似．