Fiber grating sensors for high-temperature measurement

Two fiber grating sensors for high-temperature measurements are proposed and experimentally demonstrated. The interrogation technologies of the sensor systems are all simple, low cost but effective. In the first sensor system, the sensor head is comprised of one fiber Bragg grating (FBG) and two metal rods. The lengths of the rods are different from each other. The coefficients of thermal expansion of the rods are also different from each other. The FBG will be strained by the sensor head when the temperature to be measured changes. The temperature is measured based on the wavelength-shifts of the FBG induced by the strain. In the second sensor system, a long-period fiber grating (LPG) is used as the high-temperature sensor head. The LPG is very-high-temperature stable CO2-Aaser-induced grating and has a linear function of wavelength-temperature in the range of 0 - 800 degrees C. A dynamic range of 0 - 800 degrees C and a resolution of 1 degrees C have been obtained by either the first or the second sensor system. The experimental results agree with theoretical analyses. (c) 2007 Elsevier Ltd. All rights reserved.

A novel fiber Bragg grating high-temperature sensor

A novel fiber Bragg grating (FBG) sensor for the measurement of high temperature is proposed and experimentally demonstrated. The interrogation system of the sensor system is simple, low cost but effective. The sensor head is comprised of one FBG and two metal rods. The lengths of the rods are different from each other. The coefficients of thermal expansion of the rods are also different from each other. The FBG will be strained by the sensor head when the temperature to be measured changes. The temperature is measured basis of the wavelength shifts of the FBG induced by strain. A dynamic range of 0-800 degrees C and a resolution of 1 degrees C have been obtained by the sensor system. The experiment results agree with theoretical analyses. (c) 2007 Elsevier GmbH. All rights reserved.

Miniature pulse compressor of deep-etched gratings

We propose a miniature pulse compressor that can be used to compensate the group velocity dispersion that is produced by a commercial femtosecond laser cavity. The compressor is composed of two identical highly efficient deep-etched transmissive gratings. Compared with prism pairs, highly efficient deep-etched transmissive grating pairs are lightweight and small. With an optimized groove depth and a duty cycle, 98% diffraction efficiency of the -1 transmissive order can be achieved at a wavelength of 800 nm under Littrow conditions. The deep-etched gratings are fabricated in fused silica by inductively coupled plasma etching. With a pair of the fabricated gratings, the input positively chirped 73.9 fs pulses are neatly compressed into the nearly Fourier transform-limited 43.2 fs pulses. The miniature deep-etched grating-based pulse compressor should be of interest for practical applications. (c) 2008 Optical Society of America

钛宝石强激光负载的有机硅复合凝胶增透膜研究

以硅酸四乙酯(TEOS)和甲基三乙氧基硅烷(MTEOS)为前驱材料，用溶胶-凝胶(sol-gel)方法在钛宝石表面制备得到均匀性良好且具有高激光损伤阈值的有机硅复合凝胶增透膜。膜层在钛宝石激光器输出波段(750～850nm)的增透效果显著，其平均透过率超过98．6％；激光破坏阈值为2．2J／cm^2(800nm，300ps)；膜层表面均匀性达到激光波面的要求，在皮秒、飞秒超短脉冲高功率激光领域具有应用价值。溶胶的性能测试结果表明，溶胶粘度和成膜折射率均随溶液中CH3SiO1.5溶胶体含量的增加而增大，而膜

Modified porous silica antireflective coatings with laser damage resistance for Ti:sapphire

Porous SiO2 antireflective (AR) coatings are prepared from the colloidal silica solution modified with methyltriethoxysilane (MTES) based on the sol-gel route. The viscosity of modified silica suspensions changes but their stability keeps when MTES is introduced. The refractive indices of modified coatings vary little after bake treatment from 100 to 150 Celsius. The modified silica coatings on Ti:sapphire crystal, owning good homogeneity, display prominent antireflective effect within the laser output waveband (750-850 nm) of Ti:sapphire lasers, with average transmission above 98.6%, and own laser induced damage thresholds (LIDTs) of more than 2.2 J/cm2 at 800 nm with the pulse duration of 300 ps.

Two- and three-photon absorption in a novel fluorene-based compound

A novel symmetrical charge transfer fluorene-based compound 2,7-bis (4-methoxystyryl)-9, 9-bis (2-ethylhexyl)-9H-fluorene (abbreviated as BMOSF) was synthesized and its nonlinear absorption was investigated using two different laser systems: a 140-fs, 800-nm Ti:sapphire laser operating at 1-kHz repetition rate and a 38-ps, 1064-nm Nd:YAG pulsed laser operating at 10-Hz repetition rate, respectively. Unique nonlinear absorption properties in this new compound were observed that rise from multiphoton absorption. The nonlinear absorption coefficients were measured to be 6.02

Morphological characteristics of amorphous Ge2Sb2Te5 films after a single femtosecond laser pulse irradiation

The morphology of materials resulting from laser irradiation of the single-layer and the multilayer amorphous Ge2Sb2Te5 films using 120 fs pulses at 800 nm was observed using scanning electron microscopy and atomic force microscopy. For the single-layer film, the center of the irradiated spot is depression and the border is protrusion, however, for the multilayer film, the center morphology changes from a depression to a protrusion as the increase of the energy. The crystallization threshold fluence of the single-layer and the multilayer film is 22 and 23 mJ/cm(2), respectively. (c) 2005 Elsevier B.V. All rights reserved.

Rare earth doped beta-diketone complexes as promising high-density optical recording materials for blue optoelectronics

Some kinds of rare earth beta-diketone complexes with blue-violet light absorption edge were synthesized using the ligands of thenoyltrifluoroacctone (HTTA), 2, 2'-dipyridyl (BIPY) and different metal ions (Gd3+, Sm3+ and La3+). Their contents, structures and optoelectronic parameters were monitored by elemental analysis, MS, IR and UV spectra. The solubility of rare earth beta-diketone complexes in 2, 2, 3, 3-tetrafluoro-1-propanol (TFP) and absorption properties of their films in the region 300-800 nm were measured. The influence on the difference of absorption maximum from rare earth beta-diketone complexes to beta-diketone ligand by different metal ions was studied. In addition, the thermal stability of rare earth beta-diketone complexes was also reported. (C) 2005 Elsevier B.V. All rights reserved.

Synthesis, spectroscopic properties and thermal stability of metal(II) tetraazaporphyrin complexes with two strong wavelength absorption

Three kinds of metal(II) tetraazaporphyrin complexes with blue-violet and red light wavelength absorption were synthesized by refluxing tetraazaporphyrin ligand and different metal(II) ions, respectively. Their structures were confirmed by elemental analysis, LDI-TOF-MS, FT-IR and UV-Vis. The solubility of metal(II) tetraazaporphyrin complexes in organic solvents and absorption properties of their chloroform solution and films on K9 glass in the region 250-800 nm were measured. The influence on the difference of absorption maximum from metal(II) tetraazaporphyrin complexes to tetraazaporphyrin ligand by different metal(II) ions was studied. In addition, the thermal stability of the complexes was also evaluated. (c) 2006 Elsevier Ltd. All rights reserved.

2-氨基-6-乙氧基苯并噻唑类偶氮染料及其金属鏊合物的合成及光学热学性能研究

合成了2-（2-氨基-6-乙氧基苯并噻唑基偶氮）-5-（N,N-二乙基氨基）三氟甲基磺酰苯胺偶氮染料（EBTDATFS）及其与乙酸镍、乙酸钴、乙酸铜、乙酸锌等金属盐鏊合的金属鏊合物。通过红外光谱、紫外-可见吸收光谱和MALDI质谱等对染料及其金属鏊合物进行了结构表征;使用旋涂方法在K9玻璃和抛光的单晶硅基片上制备薄膜;研究了镍金属鏊合物的热学性能;使用椭偏仪研究了Ni和Zn鏊合物的光学常数。结果表明：4种金属鏊合物薄膜最大吸收光谱为621-629nm,且长波边吸收峰陡峭;TGA-DSC测试结果表明镍金属鏊

氧化铋薄膜用于蓝光可录存储的研究

利用直流磁控溅射法在不同氧氩分压比条件下制备了BiOx薄膜。通过对薄膜在蓝光作用前后的反射率对比度变化的研究发现，氧氩分压比为50％时制备的薄膜具有最佳的光学对比度。利用X射线衍射仪(XRD)、X光电子能谱(XPS)和光谱仪研究了薄膜热处理前后的结构和光谱性质的变化。研究结果表明薄膜光学性质变化主要由薄膜中氧化铋的相变引起。蓝光静态测试结果显示氧氩分压比为50％条件下制备的BiOx薄膜具有很好好的记录敏感度，在11mW的记录功率和800ns的记录脉宽条件下，得到了52％的反射率对比度。此外，BiOx薄膜表现出了非常好的读出稳定性。

Optical properties of dye-doped zirconia films by spectroscopic ellipsometry

The optical properties of zirconia films doped with rhodamine 6G and oxazine 725 by the sol-gel process were investigated using spectroscopic ellipsometry (SE). Accurate refractive index n and the extinction coefficient k were determined using a three-oscillator classical Lorentz model in the wavelength range of 300-800 nm. The derived refractive index of dye-doped films exhibited anomalous dispersion in the absorption region. Wavelength tunable output lasing action yellow and near-infrared wavelength region was achieved by DFB configuration using zirconia films doped with R6G and oxazine 725. (c) 2006 Elsevier B.V. All rights reserved.

Comparison of Yb-doped fiber laser with one-end and double-end pumping configuration

A high-power Ytterbium-doped fiber laser (YDFL) with homemade double clad fiber (DCF) is introduced in this paper. The output power characteristics of a linear cavity fiber laser have been studied theoretically by solving the rate equations and experimentally tested with single- and double-end-pumping configurations. When both ends of the fiber are pumped by two high-power laser diodes with a launched power of similar to 300 W each, a maximum CW output of 444 W is obtained with a slope efficiency of similar to 75%. (c) 2006 Elsevier Ltd. All rights reserved.

石英玻璃表面金属沉积层的界面研究

就石英玻璃的金属化进行了初步研究，综合考虑石英玻璃管和金属的特点，合理选择金属化膜层；采用磁控溅射工艺在石英玻璃表面镀制薄膜，利用俄歇电子能谱（AES）进行了界面分析。发现膜层在沉积过程中有轻微的扩散和界面还原反应现象，后期的热处理使这种现象变得更加显著。600℃时界面扩散变得明显，Ni膜中Mo的含量达到了20％；800℃时界面扩散已经很严重，表层Ni膜渗过Mo膜进入到Ti层。因此在后期处理时，温度应控制在700℃左右。对样品灯进行了检验，加速寿命及灯头耐压检验结果均通过初步考核。

Inhomogeneous broadening, luminescence origin and optical amplification in bismuth-doped glass

Absorption and luminescence spectra and optical amplification in bismuth-doped germanate silicate glass were investigated. Two kinds of bismuth ion valence states could exist in the glass. One is Bi2+, which has shown red luminescence, another might be Bi+, which is the active center for infrared luminescence. The infrared luminescence excited at 700, 800, and 980 nm should be ascribed to the electronic transition P-3(1) --> P-3(0) of Bi+ ions in three distinct sites. The shifting, broadening, and multiple configuration of the luminescence could be due to the randomly disorder of local environment and multiple sites of the active centers. In this glass, obvious optical amplification was realized at 1300 nm wavelength when excited at 808 and 980 nm, respectively.