Careers: Survivor: The Office

Each of us must contend with office politics, because human beings are political animals, and we form alliances, negotiate deals, demand tribute, and wreak revenge. This paper discusses short list of political do's and don'ts.     

SCTS:: scanning capacitance transient spectroscopy

A new working mode of scanning capacitance microscopy (SCM) is presented, extending the possibilities of the measurement from lock-in amplitude mapping to recording of capacitance transients arising as response of abrupt bias changes. Effect of Au doping in Si on SCM and scanning capacitance transient spectroscopy (SCTS) was observed. The decay time of capacitance transient, measured locally on slightly doped region shows good agreement with the conventional DLTS results.     

The electronic and magnetic properties of wurtzite Mn∶CdS,Cr∶CdS and Mn∶Cr∶CdS∶ first principles calculations

In this article, density functional theory (DFT) based on generalized gradient approximation (GGA) and GGA+U, U is Hubbard term, is used to study the electronic properties of CdS doped with different dopants (Cr, Mn). The calculations are carried out for Mn-doped CdS, Cr-doped CdS, and co-doping of Mn/Cr in CdS simultaneously. It is found that hopping of electrons is possible with Cr:CdS and Mn:Cr:CdS while Mn:CdS does not allow the hopping of electrons. Moreover, double exchange interactions are observed in Cr:CdS and d-d super-exchange interactions are observed in Mn:CdS. Now the problem becomes interesting when one magnetic ion (Cr) supporting double exchange interactions and another ion (Mn) supporting d-d super-exchange interactions are doped simultaneously in the same system (CdS). The co-doped CdS is more stable even at high Curie temperature due to p-d double exchange interactions and d-d super exchange interactions. Furthermore, the Cr-3d and Mn-3d states present in-between the band gap are responsible for inner shell transitions and hence for optical properties. Therefore, the co-doped system is taken into account to enhance its applications in the field of spintronic and magneto-optical devices.     

Polarization switching of an er :yb :cr: phosphate glass microchip laser

We show that the light of a commercially available Er:Yb:Cr.-phosphate glass microchip laser end-pumped at 977 nm by an InGaAs laser diode can be switched between two linear polarization eigenstates when it is submitted to a polarized optical feedback. The flip occurs when the feedback phase is scanned by the external cavity length. In our experiments the laser diode light is confined to a fiber which is single-mode at pumping wavelength and the microchip laser operates in a single-longitudinal-and transverse mode. The microchip laser exhibits a self-pulsing behavior.     

PEDOT:PSS: Smart Infrared Rewritable Materials

Thermal radiation spectrum regulation plays an important role in energy and information fields. Effectively hiding targets and rendering it invisible to infrared imaging detectors are great challenges in past decades. Herein, a smart infrared rewritable and emissivity tunable polymer film is proposed based on PEDOT:PSS. The adjustment ability for the thermal emission is attributed to the mobile polaronic of PEDOT that can be effectively regulated by redox agents, resulting in an infrared emission modulation > 30%. The conformation and molecular stacking order of PEDOT also present reversible property, accompanied with the transformation between dication state and neutral state. Finally, a technique for direct writing and erasing process in the infrared region is implemented, based on the simple redox treating process. This work aims to provide a simple strategy on fabricating rewritable films based on conducting polymer PEDOT:PSS, which can be potentially applied in infrared optics security printing.     

Energy storage and heating measurements in flashlamp-pumpedCr:Nd:GSGG and Nd:YAG

The authors have experimentally measured the energy stored and the heat generated in flashlamp-pumped Cr:Nd:GSGG for three Cr³⁺ concentrations in the range of 1-2×10²⁰ ions/cm³ . It has been found that the energy storage efficiency in these samples is 1.7 times greater than that of the Nd:YAG sample, and the normalized heating parameter χ, defined as the heat deposited per unit of stored energy, is 2.5 under the specified pumping conditions, with no evident dependence on the Cr³⁺ concentration. It has been been found that the measured χ value for the sample of Nd:YAG is 2.9 for the same pumping conditions. These observed χ values exceed expected values by factors of ~1.1 and 2 for the Cr:Nd:GSGG and Nd:YAG samples, respectively. The thermal focal length in the two materials was measured showing that the lensing is shorter in GSGG by a factor of 2.6 for the same available output power, or a factor of 4.5 for the same input pump power. The expected thermal lensing was determined using measured heat loads with no adjustable parameters, achieving satisfactory agreement with measured lensing values     

Microwave cavity perturbation technique: Part III: Applications

The resonant cavity perturbation method as described in the preceding two parts of this series is applied to study the electrodynamical properties of different materials in the microwave and millimeter wave spectral range. We briefly discuss the relevant uncertainties which are asociated with the different measurement techniques and we find that employing the amplitude technique it is possible to measure both the width and frequency to nearly the same precision. We then demonstrate the broad range of applicability of this technique by showing results obtained on several different materials, ranging from an insulator to a superconductor. The performance limitations of this technique are discussed in detail.     

a-Si:C:H and a-Si:N:H Thin Films Obtained by PECVD for Applications in Silicon Solar Cells

Hydrogenated amorphous silicon-carbon (a-Si:C:H) and hydrogenated silicon-nitrogen (a-Si:N:H) antireflective films were deposited by plasma-enhanced chemical vapor deposition (PECVD) at 13.56 MHz in SiH₄ + CH₄ and SiH₄ + NH₃ gaseous mixtures of various compositions. The silicon and glass samples were investigated by optical spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). A correlation between film properties and process parameters was found. The refractive index decreased and the energy gap increased with an increase of carbon and nitrogen in the films. For some process parameters, it was possible to obtain smooth, hydrogen rich, and homogeneous films of low reflectivity. The silicon solar cells with antireflective coatings revealed an increase in efficiency.     

Nd：MgO：LiNbO_3光波导的特性

用质子交换法制备了Ｎｄ：ＭｇＯ：ＬｉＮｂＯ３波导。通过测量平面波导的二次离子质谱，得到了波导的原子组分分布，并测量了Ｎｄ：ＭｇＯ：ＬｉＮｂＯ３晶体的吸收谱线，最后利用端面耦合，分别得到了条波导内和衬底内激光诱导的荧光谱线。     

Microwave cavity perturbation technique: Part I: Principles

This report reviews the analysis used to extract the complex conductivity of a compound from a microwave cavity perturbation measurement. We intend to present a generalized treatment valid for any spheroidally shaped sample of arbitrary conductivity which is placed at either the electric or magnetic field antinode of the cavity. To begin with, we establish the relationship between the measured parameters and the conductivity for a spherical sample. Next, we extend these results to the case of spheroids; and for the first time, we cover all different configurations that one can possibly use to study an arbitrary conducting sample inside a cavity: in particular, all possible orientations of the sample with respect to the applied field are solved.     

Mg:Ce:Fe:LN晶体的生长及位相共轭分析

在Ce:Fe:LN中掺进不同摩尔分数(0,2%,4%,6%)的MgO首次以提拉法生长Mg:Ce:Fe:LN晶体,并对晶体进行极化、氧化和还原处理。测试晶体的吸收光谱和光损伤阈值。Mg:Ce:Fe:LN晶体吸收光谱吸收边相对Ce:Fe:LN晶体发生紫移。Mg:Ce:Fe:LN晶体光损伤阈值比Ce:Fe:LN晶体增大,研究了Mg:Ce:Fe:LN晶体吸收边移动机理和光损伤阈值增加机理。采用4波混频光路测试Mg:Ce:Fe:LN晶体位相共轭反射率和响应时间,Mg:Ce:Fe:LN晶体位相共轭反射率相对Ce:Fe:LN晶体降低,但响应速度增加。以x(Mg)2%(摩尔分数):Ce:Fe:LN晶体位相共轭镜消除信号光波的位相畸变。     

高平均功率室温运转闪光灯抽运Cr:Tm:Ho:YAG激光器

报道了氙灯抽运的2.1μm Cr:Tm:Ho:YAG激光器.室温下Cr:Tm:Ho:YAG为准三能级系统.振荡阈值高,掺杂离子问存在复杂的能量转移过程.采用优化掺杂浓度配比的激光晶体,长脉冲抽运,实现了室温下2.1 μm波长激光输出.采用了高漫反射陶瓷聚光腔,对有效抽运光谱带的反射率高达95%.冷却水温15℃条件下,重复频率10 Hz,获得最大平均功率23.5 w;重复频率5 Hz,获得最大激光脉冲能量2.58 J,最大斜率效率4.3%.