Polarization controlled multiwavelength switchable erbium-doped fiber laser based on high birefringence few-mode fiber loop mirror

A multiwavelength switchable erbium-doped fiber laser with linear cavity is proposed and experimentally demonstrated. It is based on a fiber loop mirror incorporating a piece of high birefringence few-mode fiber and polarization controller. Due to dependence of its reflection properties on the polarization controllers, the fiber laser can operate in the random combination of three wavelengths by only adjusting the polarization controllers in the linear cavity. The wavelengths involved in the switching operation are determined by the merged Sagnac and intermodal interferences elicited in the fiber loop mirror. The optical signal to noise extinction ratio of every oscillation line is higher than 40 dB and power fluctuation less than 0.5 dB.     

Partonic Flow and phi-Meson production in Au+Au collisions at sqrt radical sNN = 200 GeV

We present first measurements of the phi-meson elliptic flow (v2(pT)) and high-statistics pT distributions for different centralities from radical sNN=200 GeV Au+Au collisions at RHIC. In minimum bias collisions the v2 of the phi meson is consistent with the trend observed for mesons. The ratio of the yields of the Omega to those of the phi as a function of transverse momentum is consistent with a model based on the recombination of thermal s quarks up to pT approximately 4 GeV/c, but disagrees at higher momenta. The nuclear modification factor (R CP) of phi follows the trend observed in the K S 0 mesons rather than in Lambda baryons, supporting baryon-meson scaling. These data are consistent with phi mesons in central Au+Au collisions being created via coalescence of thermalized s quarks and the formation of a hot and dense matter with partonic collectivity at RHIC.     

Property changes of electroplated Cu/Co alloys and multilayers by organic additives

We investigated the change of magnetic properties of the electroplated Cu/Co alloys and multilayers caused by organic additives and high temperature annealing. When plated with a pure Cu/Co electrolyte, the alloy contained ∼25% of Cu and ∼75% of Co. The alloy was made of hcp-Co, fcc-Co and Cu(1 1 1) and was super-paramagnetic at room temperature. As we add a few organic additives in the plating electrolyte, the hcp-Co of the films disappeared. The organic additives contained in the electrolytes changed paramagnetic Cu/Co multilayers to ferromagnets. High-temperature thermal annealing increased coercivity due to the growth of the Co grains.     

Preparation of Fe–Si–B–Nb amorphous powder cores with excellent high-frequency magnetic properties

FeSiBNb amorphous powder cores were prepared with the amorphous powder by gas atomization and subsequent hot pressing of resulting powder after creating oxide layers on the amorphous powder. Fully amorphous FeSiBNb powders with good soft magnetic properties were successfully obtained in the particle size range below 100 μm. FeSiBNb amorphous powder cores exhibit stable permeability up to 10 MHz, showing excellent high-frequency characteristics.     

Nonlinear optical characteristics of monolayer MoSe2

In this study, we utilized picosecond pulses from an Nd:YAG laser to investigate the nonlinear optical characteristics of monolayer MoSe₂. Two‐step growth involving the selenization of pulsed‐laser‐deposited MoO₃ film was employed to yield the MoSe₂ monolayer on a SiO₂/Si substrate. Raman scattering, photoluminescence (PL) spectroscopy, and atomic force microscopy verified the high optical quality of the monolayer. The second‐order susceptibility χ⁽²⁾ was calculated to be ～50 pm V^?1 at the second harmonic wavelength ～810 nm, which is near the optical gap of the monolayer. Interestingly, our wavelength‐dependent second harmonic scan can identify the bound excitonic states including negatively charged excitons much more efficiently, compared with the PL method at room temperature. Additionally, the MoSe₂ monolayer exhibits a strong laser‐induced damage threshold ～16 GW cm^?2 under picosecond‐pulse excitation_. Our findings suggest that monolayer MoSe₂ can be considered as a promising candidate for high‐power, thin‐film‐based nonlinear optical devices and applications.     

Cavity Ring Down Laser Absorption Spectroscopy of NiI

用激光蒸发/反应、超声射流和光腔衰荡吸收光谱方法研究NiI在445～510 nm的吸收光谱. 发现两个新的跃迁体系[21.3]²?_5/2～X²?_5/2和[21.9]²Π_3/2～X²?_5/2,并且观察到了同位素分子⁵⁸NiI和⁶⁰NiI光谱. 同时计算得到了电子态[21.3]^{2相似文献}   

Tens of GHz Tantalum pentoxide‐based micro‐ring all‐optical modulator for Si photonics

A tantalum pentoxide‐based (Ta₂O₅‐based) micro‐ring all‐optical modulator was fabricated. The refractive index inside the micro‐ring cavity was modified using the Kerr effect by injecting a pumped pulse. The transmittance of the ring resonator was controlled to achieve all‐optical modulation at the wavelength of the injected probe. When 12 GHz pulses with a peak power of 1.2 W were coupled in the ring cavity, the transmission spectrum of the Ta₂O₅ resonator was red‐shifted by 0.04 nm because of the Kerr effect. The relationship between the modulation depth and gap of the Ta₂O₅ directional coupler is discussed. An optimized gap of 1100 nm was obtained, and a maximum buildup factor of 11.7 with 84% modulation depth was achieved. The nonlinear refractive index of Ta₂O₅ at 1.55 μm was estimated as 3.4 × 10^?14 cm²/W based on the Kerr effect, which is almost an order of magnitude higher than that of Si₃N₄. All results indicate that Ta₂O₅ has potential for use in nonlinear waveguide applications with modulation speeds as high as tens of GHz.

     

Failure of Russell-Saunders coupling in the 5f states of plutonium

Using high energy-electron energy loss spectroscopy, transmission electron microscopy, and synchrotron-radiation-based x-ray absorption spectroscopy, we provide the first experimental evidence that Russell-Saunders (LS) coupling fails for the 5f states of Pu. These results support the assumption that only the use of jj or intermediate coupling is appropriate for the 5f states of Pu. High energy-electron energy loss spectroscopy experiments were performed by use of a transmission electron microscope and are coupled with image and diffraction data; therefore, the measurements are completely phase specific.     

J/psi production versus centrality, transverse momentum, and rapidity in Au+Au collisions at square root sNN=200 GeV

The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured J/psi production for rapidities -2.2相似文献