使用Pb1-xGexTe材料提高红外薄膜光学器件温度稳定性

提高薄膜光学器件温度稳定性的一条途径是根据光学薄膜器件的稳定性理论,选择两种具有相反折射率温度系数的材料组成膜系,使材料随温度变化引起的位相变化相互抵消.但很难找到折射率温度系数可以完全相互抵消的两种材料,因此有必要找到一种折射率温度系数可以调节的材料.研究表明:红外长波材料Pb1-xGexTe的折射率温度系数可以随Ge组分x的改变而改变.研究结果证明使用Pb1-xGexTe材料,薄膜光学器件温度稳定性得到了很大的提高.     

使用Pb1-xGexTe材料提高红外薄膜光学器件温度稳定性

提高薄膜光学器件温度稳定性的一条途径是根据光学薄膜器件的稳定性理论,选择两种具有相反折射率温度系数的材料组成膜系,使材料随温度变化引起的位相变化相互抵消.但很难找到折射率温度系数可以完全相互抵消的两种材料,因此有必要找到一种折射率温度系数可以调节的材料.研究表明:红外长波材料Pb1-xGexTe的折射率温度系数可以随Ge组分x的改变而改变.研究结果证明使用Pb1-xGexTe材料,薄膜光学器件温度稳定性得到了很大的提高.     

使用Pb1—xGexTe材料提高红外膜光学器件温度稳定性

提高薄膜光学器件温度稳定性的一条途径是根据光学薄膜器件的稳定性理论,选择两种具有相反折射率温度系数的材料组成膜系,使材料随温度变化引起的位相变化相互抵消.但很难找到折射率温度系数可以完全相互抵消的两种材料,因此有必要找到一种折射率温度系数可以调节的材料.研究表明红外长波材料Pb1-xGexTe的折射率温度系数可以随Ge组分x的改变而改变.研究结果证明使用Pb1-xGexTe材料,薄膜光学器件温度稳定性得到了很大的提高.     

PbGeTe材料在长波红外低温滤光片镀制中的应用

采用目前PbTe与ZnSe材料镀制的长波红外低温滤光片时,存在低温中心波长漂移、透过率降低,膜层附着度差等缺点。介绍了一种掺锗的PbGeTe材料在长波红外低温滤光片镀制中的应用[1]。该材料能弥补PbTe材料在低温下的缺点,但常温时消光系数大。根据PbGeTe材料的特点,设计时仅把PbGeTe材料作为膜系中心间隔层,使该材料性能在滤光片中充分发挥作用。镀制出的10.8μm长波红外低温滤光片,与用单纯用PbTe材料作为膜系中心间隔层相比,在低温下,具有更好的光学性能及更强膜层附着力[2]。     

使用Pb_(1-x)Ge_xTe材料提高红外薄膜光学器件温度稳定性

提高薄膜光学器件温度稳定性的一条途径是根据光学薄膜器件的稳定性理论 ,选择两种具有相反折射率温度系数的材料组成膜系 ,使材料随温度变化引起的位相变化相互抵消。但很难找到折射率温度系数可以完全相互抵消的两种材料 ,因此有必要找到一种折射率温度系数可以调节的材料。研究表明 :红外长波材料 Pb1-x Gex Te的折射率温度系数可以随 Ge组分 x的改变而改变。研究结果证明使用 Pb1-x Gex Te材料 ,薄膜光学器件温度稳定性得到了很大的提高。     

太阳跟踪器干涉滤光片的研制与测试

根据太阳光谱在波长750nm处的光能相对比较稳定,能避免杂光干扰这一特点,研制一种太阳跟踪器干涉滤光片.采用红外石英玻璃作为基底,选择Ti2O3和SiO2作为高低折射率材料,利用台伦对称膜系等效层的概念,设计三半波干涉滤光片.通过真空镀膜和离子辅助沉积系统,研制了在波段400nm-720nm、780nm- 1000nm平均透过率低于0.1％,750nm的透过率高于91％,带宽为40nm的太阳跟踪器干涉滤光片.在制备过程中,解决了Ti2O3吸收问题;通过实验,分析了波长漂移产生的原因并提出可行办法.     

Ge-Sb-Te-O相变薄膜的光学性质研究

研究了单层 Ge- Sb- Te- O射频溅射薄膜在 40 0 nm～ 80 0 nm区域的光学常数 ( N,K)和反射、透射光谱 ,发现适当的氧掺杂能增加退火前后反射率对比度 ,因此 ,可以通过氧掺杂改良 Ge- Sb- Te相变材料的光存储性能     

薄膜干涉滤光片单色性的研究与应用

研究了薄膜干涉滤光片的单色性对生化仪和光谱分析仪实现高信噪比的重要性。通过对薄膜干涉滤光片单色性的数学分析,结合实际应用,设计和制作出的高信噪比薄膜干涉滤光片能完全符合生化检测的要求,能正确地反映出不同被检样品的特性。     

基于等效层理论的薄膜滤光片中心波长消偏振膜系设计

针对薄膜滤光片倾斜入射时产生的偏振光中心波长分离现象和偏振相关损耗,本文利用等效层理论设计了倾斜入射下中心波长消偏振的100GHz信道间隔滤光片膜系结构,实现了薄膜滤光片的角度和波长调谐。首先通过相位关系分析,计算了滤光片间隔层的消偏振等效折射率,实现了不同偏振光中心波长的对准。然后,根据等效层理论,设计三层对称膜层结构实现了对间隔层中心波长消偏振等效折射率的替换。与原有的五层规整低偏振薄膜滤光片相比,本文提出的膜系结构更为简单,对消偏振等效折射率的替换更为精确。仿真和实验结果表明:该膜系结构的薄膜滤光片能实现0~20°倾斜入射的偏振光中心波长对准,偏振光波长偏离度小于0.03nm,波长调谐范围能达到35nm。     

近紫外区域的氟化铅——冰晶石干涉膜系

我们曾用冰晶石作低折射率材料,用氟化铅作高折射率材料,镀制了近紫外区(280nm)窄带干涉滤光片。所得到的结果(T_(max)=60％,△λ=27 )重复性较好,并且膜系经过一年多仍保持其特性参数。可是,在控制蒸发方面,我们遇到了一些困难,尤其是透过率的反相问题,对此我们试图作了一些解释。     

Sensitivity-optimized long-period fiber gratings for refractive index and temperature sensing

A long-period fiber grating sensor was fabricated by periodically changing the structure of single-mode fiber with an electric arc discharge technique. After the fabrication, the refractive index and temperature sensitivities were optimized by etching the cladding with hydrofluoric acid solution. The experimental results illustrate that the thinner cladding shows relatively higher refractive index and temperature sensitivities for the same order cladding mode, which are accordant with that of numerical simulation. After the long-period fiber grating was etched for 15?min, average refractive index sensitivities of 214?nm/refractive index unit (RIU) (1.3333?–?1.3931) and 1987?nm/RIU (1.4115–1.4555) were achieved. An extremely higher refractive index sensitivity of 2731?nm/RIU appears near 1.4555. By systematically studying the temperature sensing characteristic of cladding-etched long-period fiber grating in this work for the first time, the temperature sensitivity can reach as high as 144.23?pm/°C when the ambient temperature changes from 30 to 80°C. This work provides a theoretical reference for the fabrication of a high-sensitivity refractive index and temperature sensor based on arc-induced long-period fiber grating.     

Temperature and refractive index sensor using a high-birefringence fiber loop mirror and single mode-coreless-single mode fiber structure

A novel fiber optic sensor for the simultaneous measurement of refractive index and temperature is reported. The sensor consists of a high-birefringence fiber loop mirror and a section of single mode-coreless-single mode fiber structure. The single mode-coreless-single mode fiber structure served as a refractometer while the high-birefringence fiber loop mirror was used to measure temperature. The multimode interference valley of the single mode-coreless-single mode fiber structure was sensitive to the surrounding refractive index of liquids (96.42 nm/refractive index unit) and had almost no response to temperature fluctuations. The high-birefringence fiber loop mirror was highly sensitive to temperature (1.98 nm/°C) but was insensitive to changes in refractive index. The theoretical and experimental results demonstrated simultaneous measurement of temperature and refractive index. The optimum resolution was 2.07 × 10^?4 refractive index units and 0.01°C.     

Simultaneous measurement of refractive index and temperature by integrating an external Fabry-Perot cavity with a fiber Bragg grating

A fiber sensor for simultaneous measurements of refractive index and temperature based on the integration of a fiber Bragg grating (FBG) with an external Fabry-Perot (F-P) cavity is presented. The fringe contrast of the interference spectrum generated by the F-P cavity is used to determine the external refractive index, while the wavelength shift of the FBG is used to measure temperature. The result showed that the refractive index and temperature sensitivity for the integrated sensor is 8.1 × 10(-6) and 0.01006 nm/°C, respectively.     

折射率温度系数测定仪中数据自动采集处理系统的研究

本文介绍了折射率温度系数测定仪的数据自动采集系统。研究了用微计算机对能量及周期均有变化状态下,干涉条纹随温度变化量的采集及处理的硬件及软件。实验中干涉条纹测量精度达±0.06。温度测量精度达±0.5℃。满足了折射率温度系数达±6×10^-7/℃的精度要求。     

High temperature superconductor micro-superconducting-quantum-interference-device magnetometer for magnetization measurement of a microscale magnet

We have developed a high temperature superconductor (HTS) micrometer-sized dc superconducting quantum interference device (SQUID) magnetometer for high field and high temperature operation. It was fabricated from YBa2Cu3O7-delta of 92 nm in thickness with photolithography techniques to have a hole of 4x9 microm2 and 2 microm wide grain boundary Josephson junctions. Combined with a three dimensional magnetic field coil system, the modulation patterns of critical current Ic were observed for three different field directions. They were successfully used to measure the magnetic properties of a molecular ferrimagnetic microcrystal (23x17x13 microm3), [Mn2(H2O)2(CH3COO)][W(CN)8]2H2O. The magnetization curve was obtained in magnetic field up to 0.12 T between 30 and 70 K. This is the first to measure the anisotropy of hysteresis curve in the field above 0.1 T with an accuracy of 10(-12) J T(-1) (10(-9) emu) with a HTS micro-SQUID magnetometer.     

Simultaneous measurement of refractive index and temperature based on a long period fiber grating inscribed in a photonic crystal fiber with an electric-arc discharge

A novel fiber sensor composed by two single mode fibers and long period fiber grating based on a photonic crystal fiber prepared by periodic discharge heating has been experimentally investigated to measure refractive index and temperature. A Mach-Zehnder interferometer was formed due to the presence of two fusion spliced collapsed regions in the photonic crystal fiber. The resonance dip and interference pattern were differently influenced by the ambient disturbance, so the dual-parameters were simultaneously measured by analyzing the characteristics of transmission spectrum. After the experimental measurements, refractive index and temperature sensitivities of 117.28?nm/RIU and ?86.29?pm/°C were realized. Therefore, the reported sensor with advantages of easy fabrication, simple structure, and small size has the potential for simultaneous refractive index and temperature measurements involving biochemical sensing applications.     

低压反应离子镀制备Ge1-xCx薄膜的硬度研究

应用低压反应离子镀的薄膜制备方法在G e基底上沉积了G e1-xCx薄膜,随着沉积速度在0.1nm/s~0.9nm/s之间变化,G e1-xCx薄膜的硬度在2.12 GPa~11.066 GPa之间可变,当沉积速率为0.9nm/s时,G e1-xCx薄膜最大硬度为11.066 GPa。XRD测试结果表明,沉积的G e1-xCx薄膜均为无定形结构。对薄膜稳定性和牢固度的测试表明,制备的G e1-xCx薄膜在具有较高的硬度的同时,也有良好的性能。     

The development of Thomson scattering system on HL-2A tokamak

A new Thomson scattering diagnostic system is successfully developed to measure core plasma electron temperature (Te) and density (ne) of HL-2A tokamak (major radius R=165 cm, minor radius a=40 cm). In this system, a standard lamp-monochromator combination is utilized for the calibration of spectral responses. By sweeping in the range of 750-1200 nm with a step of 2 nm, the work can be done automatically for one-point calibration and then for other. Electronic gain calibration and gain monitoring are done by pulsed light emitting diode light. By utilizing an intense Nd:YAG laser of pulse energy up to 4 J and employing good quality interference filters in the five-channel filter polychromator to surpress greatly the stray light, the TS system can be routinely used to make measurements with good quality data. After each HL-2A plasma discharge, the measured Te and ne data are transferred to HL-2A database for lookup and analyses.     

UV-reflecting wing scales in the silk moth Antheraea assamensis: its biophysical implications

Scanning electron microcopy of the wing scales from some specific locations in the silk moth, Antheraea assamensis, revealed the presence of 50-60-nm-thick microridges and 80-nm-thick air spaces between them. The principle of optics suggests that when the measured average thickness of microridges or lamellae is about 50-60 nm, that of the air-space between them is about 80-82 nm, then due to the known refractive index of air (1.0) and the infrared refractive index of lamellar cuticle (1.60), the lamellae (microridges) and the intervening lamellar air spaces will have similar optical thickness. A common optical thickness for the two types of layers causes the microridge structures to function in the fashion of a quarter wavelength interference filter and to reflect UV light. Behavioral studies under the natural conditions and short experimental exposure of the moths to artificial UV light suggests that coupling behavior of the moth is governed to a significant extent by these UV-reflecting wing scales. The importance of the study in overcoming a major problem of low autocoupling efficiency of moths in the Muga Silk Industry is discussed with the help of relevant literature.