主三镜一体化离轴三反光学天线设计

为提高空间激光通信离轴三反光学天线的装调效率,需要对反射镜总的装调自由度进行优化设计。基于共轴三反无焦系统的设计原理,提出一种主三镜一体化的设计方法,并推导了光学系统结构参数之间的关系,利用Zemax光学软件设计了一种结构紧凑、主三镜一体化的离轴三反光学天线。设计结果表明:全视场光学像质优于衍射极限,主镜和三镜空间位置相接近,可共母板加工和面形共基准检测,为主三镜的一体化加工提供了方法。光学天线的装调自由度减少了6个,降低了装调难度,提高了装调效率。     

光寻址电位传感器的正交相位检波检测方法

光寻址电位传感器的幅度检测方法易受噪声干扰,灵敏度差,信噪比和精度低,且受调制光源的影响较大,影响检测结果的准确性.为此提出了一种基于正交相位检波的光寻址电位传感器检测方法.该方法是将光寻址电位传感器的输出光电流信号分别与两路正交信号相乘,通过低通滤波提取直流分量并相除,即可得到光寻址电位传感器的输出信号相位信息.与已有的光寻址电位传感器相位检测方法相比,该方法具有算法复杂度低、实时性高的优点.实验研究了调制光源光强对光寻址电位传感器幅度检测和相位检测的影响,对比分析了光寻址电位传感器的传统幅度检测方法与正交相位检波检测方法对pH检测的灵敏度、线性度及信噪比.结果表明,相比于幅度检测方法,调制光源光强对光寻址电位传感器的相位检测影响更小,在频率为10 kHz,pH的范围为1.68~10.01的情况下,相位检测方法比幅度检测方法测得的灵敏度增加了7 mV/pH,精度提高了14.9 mpH,非线性误差减小了0.003%,均方差减少了0.1051×10^-5,信噪比增加了8.2827 dB.该方法特别适用于弱光下的光寻址电位传感器检测.     

光子晶体光纤温度压力传感器

提出了一种在高温环境下同时测量温度和气压的光子晶体光纤温度压力传感器.在普通单模光纤和光子晶体光纤之间熔接一段空心光纤构成干涉结构.空心光纤段构成非本征法布里-珀罗干涉仪,利用光子晶体光纤的微孔与外界相通,通过气体折射率变化来测量环境中的气压变化;光子晶体光纤段构成本征法布里-珀罗干涉仪,利用热膨胀效应和热光效应来测量环境中的温度.传感器的解调通过自制的白光干涉解调仪实现,实验通过测量腔长得到被测环境的温度和气压.在不同温度和气压环境下,对腔长分别为306μm和1535μm的温度压力光纤传感器进行连续测量.实验结果表明,传感器能够在28~800℃的温度下和0~10 MPa的气压下稳定工作,测量范围内温度灵敏度可达17.4 nm/℃,压力灵敏度随温度增加而降低,在28℃时可达1460.5 nm/MPa.     

超越SNOM探针通光孔径尺寸的金属纳米间隙超分辨测量

采用电磁场有限元方法,数值模拟了孔径型扫描近场光学显微镜(aperture Scanning Near-field Optical Microscopy,a-SNOM)在照明模式下的工作过程.针对金偶极天线结构,改变天线长度和纳米间隙尺寸,计算了a-SNOM探针孔径的远场辐射速率随探针端面中心坐标变化的扫描曲线,实现了超越a-SNOM探针通光孔径尺寸的天线金属纳米间隙的超分辨测量,对于100nm通光孔径的探针,可分辨最小尺寸为10nm(0.016倍波长)的金属间隙.通过对比金属和介质偶极天线的a-SNOM探针远场辐射速率测量的计算结果,表明天线金属纳米间隙的超分辨测量的实现是由于金属间隙表面等离激元的激发.     

具有感存算一体化的新型神经形态视觉传感器

传统的数字图像处理系统包括图像传感器与图像处理单元,二者在物理空间上分离,图像信息在其间的传输造成了延时与能耗。此外,数字图像传感器基于“帧”的工作原理,可能丢失一些重要信息,或者造成数据冗余。人类视觉系统提供了一种高效并行的信息处理方式。神经形态视觉传感器能够模拟人类视网膜的功能,同时具备感知光信号、存储信号和进行信息预处理的功能。这类感存算一体化的神经形态视觉传感器简化了人工视觉系统的电路复杂性,提升了信息处理效率,节省了系统功耗。文章总结了传统的数字图像传感器存在的问题,介绍了几种重要的人工神经网络,讨论了新型神经形态视觉传感器的研究进展和存在的问题。     

Spectral polarization-encoding of broadband laser pulses by optical rotatory dispersion and its applications in spectral manipulation

We propose a kind of spectral polarization-encoding(SPE) for broadband light pulses, which is realized by inducing optical rotatory dispersion(ORD), and decoded by compensating ORD. Combining with polarization-sensitive devices, SPE can not only work to control polarization-dependent transmission for central wavelength or bandwidth-tunable filtering, but also can be used for broadband regenerative or multi-pass amplification with a polarization-dependent gain medium to improve output bandwidth. SPE is entirely passive thus very simple to be designed and aligned. By using an ORD crystal with a good transmission beyond 3-μm mid-infrared region, e.g., Ag Ga S_2, SPE promises to be applied for the wavelength tuning lasers in mid-infrared region, where the tunning devices are rather under developed compared with those in visible and near-infrared region.     

Crystal growth,structure and optical properties of Pr~(3+) -doped yttria-stabilized zirconia single crystals

The development of blue semiconductor light-emitting diodes(LEDs) has produced potential applications for Prdoped materials that can absorb blue light, especially crystals, and we now report structure and optical properties for high-quality Pr-doped single crystals of yttria-stabilized zirconia(YSZ) grown by the optical floating zone(FZ) method.X-ray diffraction(XRD) and Raman spectroscopy showed that all of the single crystal samples were in the cubic phase,whereas the corresponding ceramic samples contained a mixture of monoclinic and cubic phases. X-ray photoelectron spectroscopy(XPS) and electron paramagnetic resonance(EPR) spectroscopy showed that Pr was present as the Pr~(3+) ion in ceramic rods and single crystals after heating to high temperatures. The absorption and photoluminescence excitation(PLE) spectra of the Pr-doped YSZ crystals measured at room temperature showed strong absorption of blue light, while their photoluminescence(PL) spectra showed five emission peaks at 565 nm, 588 nm, 614 nm, 638 nm, and 716 nm under450 nm excitation. The optimum luminescence properties were obtained with the crystal prepared using 0.15 mol% Pr_6O_(11),and those with higher concentrations showed evidence of quenching of the luminescence properties. In addition, the color purity of Pr-doped YSZ single crystal reached 98.9% in the orange–red region.     

Temperature and current sensitivity extraction of optical superconducting transition-edge sensors based on a two-fluid model

Optical superconducting transition-edge sensor(TES) has been widely used in quantum information, biological imaging, and fluorescence microscopy owing to its high quantum efficiency, low dark count, and photon number resolving capability. The temperature sensitivity(α_I) and current sensitivity(β_I) are important parameters for optical TESs, which are generally extracted from the complex impedance. Here we present a method to extract α_I and β_I based on a twofluid model and compare the calculated current–voltage curves, pulse response, and theoretical energy resolution with the measured ones. This method shows qualitative agreement that is suitable for further optimization of optical TESs.     

新型富勒烯衍生物的光限幅研究

应用倍频Ｎｄ∶ＹＡＧ脉冲激光，在波长为５３２ｎｍ、脉冲宽度分别为８ｎｓ和２３ｐｓ的条件下，研究了新型富勒氮烯乙酰氨衍生物（Ｎ－ａｃｅｔａｍｉｄｅ１，２－ｄｉｈｙｄｒｏ－１，２－ａｚａ－ｆｕｌｅｒｅｎｅ［６０］）的反饱和吸收与光限幅特性。实验结果表明，同脉宽为纳秒的激发脉冲相比，富勒烯乙酰氨衍生物对脉宽为皮秒的脉冲限幅效果比较好。     

Measurement of Solid-gas Two-phase Flow using Optical Fiber Sensor

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