【摘 要】
：
In this paper, we present the design of a new photonic crystal fiber (PCF) gas sensor for evanescent-field sensing in terahertz (THz) wave band. This sensor can be used to identify the gas, and its size is very large, so that it is beneficial to fill it w
【机 构】
：
TianjinKeyLab.ofFilmElectronic
【出 处】
：
OptoelectronicsLetters
论文部分内容阅读
In this paper, we present the design of a new photonic crystal fiber (PCF) gas sensor for evanescent-field sensing in terahertz (THz) wave band. This sensor can be used to identify the gas, and its size is very large, so that it is beneficial to fill it with the test substance. Based on simulation, we demonstrate that the gas sensor using PCFs with four noncircular large holes in the cladding has high sensitivity and low loss, the confinement loss is less than 0.007 dB/m, and the bending loss is very small. The new PCF gas sensor can detect kinds of gases, for example, if test gas is water vapor, it has obvious absorption peaks in THz band, and the sensitivities of gas sensor are 64% and 73% at 1.097 THz and 0.752 THz, respectively. Due to the ultra-low loss and high sensitivity of the model, the novel steering-wheel structured fiber is very suitable for evanescent-field sensing and the detection of chemical and biological products.
其他文献
分析了Nd∶YAG板条中产生强烈放大自发辐射(ASE)的原因,开展了抑制高增益激光板条中ASE的理论和实验研究。抽运光占空比为8%,峰值抽运功率为21.38 kW,波长为1064 nm连续探测光的注入光强为4 W/cm
2,在Nd∶YAG板条上、下表面镀制普通倏逝膜和多层复合膜时探测光功率的放大倍率分别为1.82和1.92,Nd∶YAG板条总储能增大了4.6%。实验结果表明:通过对Nd∶YAG板条上、下表面镀制多层复合膜,可在一定程度上抑制板条内的ASE效应,增大
目前运转的绝大多数激光测距系统属于第一代系统，它们利用腔倒空或Q开关红宝石激光器及时间间隔计数器，精度能达10~100厘米。第二代系统采用锁模Nd:YAG激光器和出现信号的计时器，目前正在研制，现在已能制成紧凑的大部分为自动的，全机动的测距站，能对高空卫星及月球测距，精度达几厘米。用条纹管作探测器，并在两个波长处测定以补偿大气传输的变化，可获得更高的精度。
提出在照射型莫尔轮廓法中存在着原理性误差,导出校正此类误差的计算公式。用实验拍摄锥形试件的莫尔轮廓,经过对照片的判读和计算,证实了所提供公式的正确性。
载玻片在液体光学测量、微生物学和基因学等领域实验中应用广泛, 其光学性能直接影响实验结果。提出了透射法测量载玻片光学常数的方法, 建立了载玻片透射比计算模型及其光学常数反演模型。通过TU-19双光束可见光分光光度计测量1.5mm和2.0mm厚度载玻片样品在310~600nm波长范围的透射光谱, 结合透射光谱利用光学常数反演模型, 得到了载玻片的光学常数。结果表明, 载玻片的衰减系数在10-6~10-8之间, 折射率在1.5~3.3之间。
The effect of speckle pattern on laser Doppler velocimeters is studied theoretically and experimentally. We have found that dynamic speckle patterns can cause error in velocity measurement. Increasing sampling time and using proper signal processing circu
建立了一个零缺陷周期性，正、负缺陷非周期性三种宇称-时间(PT)对称晶格势中奇异光孤子传输的理论模型。运用变分法分析了零缺陷晶格势中孤子的宽度和势能的变化，并运用线性稳定性分析研究了孤子的稳定性范围。结果表明，在一定的参数范围内，奇异光孤子在PT晶格势中能够存在并稳定传输。
激光聚变方案是基于用聚焦的激光束点燃燃料小球。要使激光途径获得成功，必须使这种燃料向心爆炸到10000倍于正常的液体密度。
对80 mm孔径玻璃体吸收激光能量计的接收面响应均匀性进行了测试研究。结果表明,选择合适的接收盘材料、厚度以及半导体热电组件的分布,可以改善均匀性,均匀性偏差可以达到±2.1％以内。
光泵Na2超声束虽然激光输出很低，但由于其内自由度的有效冷却和分子快速通过相互作用区，使其成为高增益介质。这些优点是几年前西德凯泽斯劳腾大学的K. Bergann组发现的。
Traditional color-based mean shift tracking algorithm is unable to accurately track the object. To address this problem, we present an improved tracking algorithm. The improved tracker integrates the color and motion cues which characterize the appearance