An optically-pumped multigas Far-IR laser

We report here the operation of an optically-pumped multigas Far-IR laser. In our experiment, three different gases (CH₃OH, CH₃Br, CH₃I) were simultaneously introduced into the Far-IR cavity. By adjusting the partial pressures of the gases and by tuning the appropriate CO₂ laser pump line, we were able to obtain the laser action for each one of them as efficiently as is observed when the gases are present by themselves.     

Magnetospectroscopy of double HgTe/CdHgTe QWs with inverted band structure in high magnetic fields up to 30 T

Magnetoabsorption in far and mid IR ranges in double HgTe/CdHgTe quantum wells with inverted band structure has been studied in high magnetic fields up to 30 T. Numerous intraband and interband transitions have been revealed in the spectra and interpreted within axial 8 × 8 k·p model. Splitting of dominant magnetoabsorption lines resulting from optical transitions from hole-like zero-mode Landau level has been discovered and discussed in terms of a built-in electric field and collective phenomena.     

CIRCE: a dedicated storage ring for coherent THz synchrotron radiation

We present the concepts for an electron storage ring dedicated to and optimized for the production of stable coherent synchrotron radiation (CSR) over the far-infrared terahertz wavelength range from 200 μm to about 1 cm. CIRCE (Coherent InfraRed CEnter) will be a 66 m circumference ring located on top of the ALS booster synchrotron shielding tunnel and using the existing ALS injector. This location provides enough floor space for both the CIRCE ring, its required shielding, and numerous beamlines. We briefly outline a model for CSR emission in which a static bunch distortion induced by the synchrotron radiation field is used to significantly extend the stable CSR emission towards higher frequencies. This model has been verified with experimental CSR results. We present the calculated CIRCE photon flux where a gain of 6–9 orders of magnitude is shown compared to existing far-IR sources. Additionally, the particular design of the dipole vacuum chamber has been optimized to allow an excellent transmission of these far-infrared wavelengths. We believe that the CIRCE source can be constructed for a modest cost.     

The dispersion of the lasing medium and optimum length of the sample tube of OPFIRL

The dispersive characteristic of the optically pumped FIR laser (OPFIRL) system had been studied theoretically. It was found that the refractive index of the lasing medium was not a constant in the OPFIRL, and the approximate value n=1 must be corrected, otherwise, it will lead to a large error for theoretical calculation of the optimization of the operating parameters of the OPFIRL. The value of n as function of (Ip, Is, x, y, z, P) was calculated theoretically. The additional losses due to the energy exchange between the lasing system and the molecules populated in the energy levels except the appointed three-level system was estimated. The calculated optimum length of the sample tube of OPFIRL with the corrected theory was in pretty good agreement with the experimental result.Supported by national science foundation of PRC     

Synthesis of aurocyanide and auricyanide complexes of phosphines,phosphine sulfides and phosphine selenides,and their characterization by IR,far-IR,UV solution,and solid-state NMR spectroscopic methods

A series of aurocyanide and auricyanide complexes of phosphines, phosphine sulfides, and phosphine selenides were synthesized. These new complexes have the general formula [L _n Au(CN) _m ], where L could be Cy₃P, (2-CN-Et)₃P, Me₃PS, Et₃PS, Ph₃PS, Me₃PSe, or Ph₃PSe. Auricyanide was reacted with L at 1?:?2 ratio. Products were characterized using elemental analysis, melting point, UV, IR, far-IR solution, and solid-state NMR spectroscopy. Phosphine ligands cause gold(III) reduction to gold(I); less redox tendency was found for phosphine sulfides and phosphine selenides. Tri-coordinate complexes [L₂AuCN] were produced from phosphine ligands with gold-tetracyanide. IR and UV spectroscopic methods were used to identify gold oxidation state in the synthesized complexes.     

高压下DPP-11超分子结构中的π-π相互作用

通过金刚石对顶砧(DAC)高压装置产生高压, 利用原位高压同步辐射能量色散X射线衍射(EDXD)和同步辐射远红外光谱研究了压力对DPP-11[2,5-二-(11-十一醇基)-3,6-二-(2-噻吩基)-1,4-二酮吡咯并[3,4-c]吡咯]固体及其在水溶液中胶束体系的影响. 实验结果表明, 在准静水压条件下, DPP-11固体没有发生相变, 但随着压力的增加, 分子间的π-π相互作用明显增强. 在DPP-11胶束中发现了DPP-11固体中新的远红外吸收峰, 此峰随着压力的增加而蓝移, 这是由于胶束中π共轭染料基团的π-π相互作用增强所致.     

A series of CdIIX2 (X = Cl,Br, I) complexes with D-A model and their third-order nonlinear optical properties with a femtosecond laser in the near IR region

A series of D-A-type Cd^IIX₂L (X = Cl, Br, I) complexes with asymmetric structures was designed, synthesized, and fully characterized. Structural studies indicate that Cd(II) has five-coordination with three N from terpyridine and two halides to form distorted square pyramidal complexes. The stereostructure of the metal complexes effectively reduces interactions between the complex molecules avoiding fluorescence quenching of the metal complexes in the solid state. The Cd(II) complexes also showed strong two-photon absorption in the near-infrared range by aperture Z-scan technique using a femtosecond laser in the solid state, with excellent two-photon absorption coefficients. The band gaps of the complexes suggested that they have potential applications in semiconductor materials and may be useful in near-IR nonlinear optical materials.     

胆酸和脱氧胆酸分子的远红外与THz吸收光谱研究

胆酸和脱氧胆酸是胆汁酸中的主要成分, 是人体中重要的生物表面活性剂. 两种分子只相差一个羟基, 在远红外和太赫兹波段有不同的吸收光谱. 胆酸分子的太赫兹(THz)吸收光谱有1.26 THz(42 cm-1)和2.02 THz(67 cm-1)两个吸收峰, 脱氧胆酸分子的THz吸收光谱有1.13, 1.26, 1.69和2.17 THz(即38, 42, 56, 72 cm-1)等几个吸收峰. 两个分子的THz吸收光谱都包含有1.26 THz(42 cm-1) 峰, 反映出二者结构的相似性. 它们的远红外光谱都有部分频率相近的谱带, 但对比之下可以观察到峰位位移和相对峰强的改变. 指认了两种物质的某些可能与羧基振动有关的特征吸收峰. 为找出THz光谱隐含的信息, 利用Omnic程序采用二阶导数方法来处理THz光谱数据, 观察到多个子峰, 说明分子结构中可能存在更复杂的氢键状态. 实验结果表明, 远红外和THz吸收光谱是研究生物分子及鉴别生物分子结构的很好方法.