LWIR/SWIR switchable two color device based on InP/InGaAs integrated HBT/QWIP

A novel two color infrared (IR) device that allows fast electrical switching between the short wavelength IR (SWIR) band (0.9–1.6 μm) and the long wavelength IR (LWIR) band (8–12 μm) is presented. The integrated sensor is based on MOCVD grown, lattice matched (to InP substrate) epilayers of InGaAs/InP and consists of two, monolithically integrated sections of heterojunction bipolar transistor (HBT) and quantum well infrared photodetector (QWIP).     

短波红外昼光恒星成像光学系统设计

由于太阳光散射在地球大气中产生的背景辐射使得可见光传感器极易饱和,导致在白天测星很困难。通过分析可知,红外传感器在白天测星的概率比可见光传感器要高得多。针对红外测星特点,介绍了一种短波红外光学系统的设计方法,给出了一种工作波长为2．0～2．5μm,相对孔径为1．4,焦距为140mm的镜头设计过程。该镜头结构紧凑,用材特殊,能适应-50～70℃的环境要求．实现全天候测星。     

Xanthene-Based Nitric Oxide-Responsive Nanosensor for Photoacoustic Imaging in the SWIR Window

Shortwave infrared (SWIR) dyes are characterized by their ability to absorb light from 900 to 1400 nm, which is ideal for deep tissue imaging owing to minimized light scattering and interference from endogenous pigments. An approach to access such molecules is to tune the photophysical properties of known near-infrared dyes. Herein, we report the development of a series of easily accessible (three steps) SWIR xanthene dyes based on a dibenzazepine donor conjugated to thiophene ( SCR-1 ), thienothiophene ( SCR-2 ), or bithiophene ( SCR-3 ). We leverage the fact that SCR-1 undergoes a bathochromic shift when aggregated for in vivo studies by developing a ratiometric nanoparticle for NO ( rNP-NO ), which we employed to successfully visualize pathological levels of nitric oxide in a drug-induced liver injury model via deep tissue SWIR photoacoustic (PA) imaging. Our work demonstrates how easily this dye series can be utilized as a component in nanosensor designs for imaging studies.     

高稳定度可见/短波红外在轨相对定标监测系统关键技术研究

针对高稳定度遥感器在轨相对定标监测系统关键技术进行研究,阐述了工作原理和关键技术。研制了基于可见/短波红外双波段陷阱结构的高稳定度定标探测器组件,通过选择高灵敏度单元可见和短波红外光电探测器,一方面使探测器组件工作在线性更好、暗电流更低的零偏置光伏电路模式,另一方面使探测器组合成为复合型陷阱光机探测模式,并在模拟前放电路和数据采集环节进行了关键参数设计,完成了星载定标辐射源输出辐射的高稳定度相对定标监测系统设计。通过实验室内积分球以及国家计量技术机构提供的标准灯的辐射测试结果表明,系统获取的码值相对标准方差达到0.030%～0.046%(可见通道)和0.040%～0.059%(短波红外通道),实现了相对定标系统的高稳定度监测,为未来遥感器在轨相对定标提供一种优良的解决方案。     

融合可见光-近红外与短波红外特征的新型植被指数估算冬小麦LAI

考虑到短波红外特征与叶面积指数(LAI)有很好的关联,将短波红外特征的典型水分指数与基于可见光-近红外特征的植被指数相融合,尝试构建新的植被指数估算作物LAI。通过PROSAIL辐射传输模型分析新植被指数对LAI饱和响应的特征;利用2009年和2008年北京地区冬小麦实测光谱数据进行LAI估算建模与验证。结果表明：所选择的10个典型可见光-近红外植被指数分别与5个水分植被指数相结合构建的新指数,都能够有效提高与LAI的相关性,特别是在融合了含有短波红外特征的sLAIDI*指数后,新指数显著提高了对LAI响应的饱和点,而对植被水分变化不敏感,LAI估算精度得到改善。研究表明：将短波红外特征引入到可见光-近红外植被指数中,构建的新植被指数对冬小麦LAI估算具有明显的优势。     

Tailoring the NIR-II Photoluminescence of Single Thiolated Au25 Nanoclusters by Selective Binding to Proteins**

Atomically precise gold nanoclusters are a fascinating class of nanomaterials that exhibit molecule-like properties and have outstanding photoluminescence (PL). Their ultrasmall size, molecular chemistry, and biocompatibility make them extremely appealing for selective biomolecule labeling in investigations of biological mechanisms at the cellular and anatomical levels. In this work, we report a simple route to incorporate a preformed Au₂₅ nanocluster into a model bovine serum albumin (BSA) protein. A new approach combining small-angle X-ray scattering and molecular modeling provides a clear localization of a single Au₂₅ within the protein to a cysteine residue on the gold nanocluster surface. Attaching Au₂₅ to BSA strikingly modifies the PL properties with enhancement and a redshift in the second near-infrared (NIR-II) window. This study paves the way to conrol the design of selective sensitive probes in biomolecules through a ligand-based strategy to enable the optical detection of biomolecules in a cellular environment by live imaging.     

Implementation of a novel low‐noise InGaAs detector enabling rapid near‐infrared multichannel Raman spectroscopy of pigmented biological samples

Pigmented tissues are inaccessible to Raman spectroscopy using visible laser light because of the high level of laser‐induced tissue fluorescence. The fluorescence contribution to the acquired Raman signal can be reduced by using an excitation wavelength in the near infrared range around 1000 nm. This will shift the Raman spectrum above 1100 nm, which is the principal upper detection limit for silicon‐based CCD detectors. For wavelengths above 1100 nm indium gallium arsenide detectors can be used. However, InGaAs detectors have not yet demonstrated satisfactory noise level characteristics for demanding Raman applications. We have tested and implemented for the first time a novel sensitive InGaAs imaging camera with extremely low readout noise for multichannel Raman spectroscopy in the short‐wave infrared (SWIR) region. The effective readout noise of two electrons is comparable to that of high quality CCDs and two orders of magnitude lower than that of other commercially available InGaAs detector arrays. With an in‐house built Raman system we demonstrate detection of shot‐noise limited high quality Raman spectra of pigmented samples in the high wavenumber region, whereas a more traditional excitation laser wavelength (671 nm) could not generate a useful Raman signal because of high fluorescence. Our Raman instrument makes it possible to substantially decrease fluorescence background and to obtain high quality Raman spectra from pigmented biological samples in integration times well below 20 s. Copyright © 2015 John Wiley & Sons, Ltd.     

天文导航光电测星能力的计算方法

天文导航可全面地提供位置、航向、姿态和速度等核心导航信息,特别是在复杂电磁环境下,发挥着独特的重要作用。测星能力是天文导航设备的核心指标之一,提出了光电通道测星的信噪比和调制度的计算公式和参数选取说明,给出了短波红外测星设备的计算实例和实测结果,结果表明短波红外测星可显著延长测星时段。     

短波红外平场光谱仪的波长定标

针对自行研制的短波红外平场光谱仪,讨论了波长定标的原理和方法.短波红外平场光谱仪由两个分光探测单元组成,探测单元以平场凹面光栅分光,处于焦平面上的线阵列探测器探测,波长定标分为两个波段进行.为了实现准确的波长定标,针对短波红外平场光谱仪的特点设计了波长定标步骤.双单色仪可以输出光谱仪波长范围内任意波长单色光,选用双单色仪作为光谱定标光源,双单色仪的输出单色光光潜分辨力为1.5 nm,经过光谱仪的分光会聚后成像在线阵列探测器像元上,采用重心法计算出给定波长对应的像元精确位置,通过多项式拟合得出两个探测单元的波长定标系数.定标结果表明,在900～2400 nm波长范围内,定标曲线拟合误差小于0.5 nm,波长定标不确定度优丁0.6 nm.