High quantum efficiency long-/long-wave dual-color type-Ⅱ InAs/GaSb infrared detector

A long-/long-wave dual-color detector with N-M-π-B-π-M-N structure was developed based on a type-Ⅱ InAs/GaSb superlattice. The saturated responsivity was achieved under low bias voltage for both channels. The device could be operated as a single detector for sequential detection and showed high quantum efficiencies. The peak quantum efficiencies of long-wavelength infrared band-1(blue channel) and long-wavelength infrared band-2(red channel) were 44% at 6.3 μm under 20 mV and 57% at 9.1 μm under-60 mV, respectively. The optical performance for each channel was achieved using a 2 μm thickness absorber. Due to the high QE, the specific detectivities of the blue and red channels reached5.0×10^(11) cm·Hz^(1/2)/W at 6.8 μm and 3.1×10^(11) cm·Hz1^(1/2)/W at 9.1 μm, respectively, at 77 K.

Effect of Nanorod Diameters on Optical Properties of GaN-Based Dual-Color Nanorod Arrays

Dual-color(blue and green) InGaN/GaN nanorod light-emitting diodes(LEDs) with three different nanorod diameters are fabricated. Enhancement of luminescence intensity per area is observed in blue and green wells,to varying degrees. When the diameter is 40 nm, it sharply decreases, which could be explained by the sidewall nonradiative recombination. Time-resolved photoluminescence is conducted to study the carrier lifetime. High recombination rate is observed in nanorod arrays, and is an order of magnitude less than that of the planar LED.When the diameter is 40 nm, the nonradiative lifetime decreases, and this explains the decrease of intensity. The3 D-FDTD simulations show the enhancement of light extraction out of geometry structure by calculating the transmittance of the nanorod arrays.

Fusion of clathrin and caveolae endocytic vesicles revealed by line-switching dual-color STED microscopy

Clathrin-and caveolae-mediated endocytosis are the most commonly used pathways for the internalization of cell membrane receptors.However,due to their dimensions are within the diffraction limit,traditional fluorescence microscopy cannot distinguish them and little is known about their interactions underneath cell membrane.In this study,we proposed the line-switching scanning imaging mode for dual-color triplet-state relaxation(T-Rex)stimulated emission depletion(STED)super-resolution microscopy.With this line-switching mode,the cross-talk between the two channels,the side effects from pulse picker and image drift in frame scanning mode can be effectively eliminated.The dual-color super-resolution imaging results in mixed fluorescent beads validated the excellent performance.With this super-resolution microscope,not only the ring-shaped structure of clathrin and caveolae endocytic vesicles,but also their semi-fused structures underneath the cell membrane were distinguished clearly.The resultant infor-mation will greatly facilitate the study of clathrin-and caveolae-mediated receptor endocytosis and signaling process and also our home-built dual-color T-Rex STED microscope with this line-switching imaging mode provides a precise and convenient way to study subcellular-scale protein interactions.

Field-free molecular orientation induced by combined femtosecond single-and dual-color laser pulses: The role of delay time and quantum interference

The coherent control of field-free molecular orientation of CO with combined femtosecond single- and dual-color laser pulses has been theoretically studied. The effect of the delay time between the femtosecond single- and dual-color laser pulses is discussed, and the physical mechanism of the enhancement of molecular orientation with pre-alignment of the molecule is investigated. It is found that the basic mechanism is based on the creation of a rotational wave packet by the femtosecond single-color laser pulse. Furthermore, we investigate the interference between multiple rotational excitation pathways following pre-alignment with femtosecond single-color laser pulse. It is shown that such interference can lead to an enhancement of the orientation of CO molecule by a factor of 1.6.

InAs/InAsSb超晶格红外中/中波双色焦平面探测器研制

超晶格材料已经成为了第三代红外焦平面探测器的优选材料。双波段红外探测器能够通过对比两个波段内的光谱信息差异,对复杂的背景进行抑制,提高探测效果,在需求中尤为重要。本文开展了InAs/InAsSb超晶格中/中双色焦平面探测器设计及制备技术研究,从器件设计、材料外延、芯片加工等方面展开研究,制备了中心距30μm的320×256 InAs/InAsSb二类超晶格中/中波双色焦平面探测器。器件短中波峰值探测率达到7.2×10^(11)cm·Hz^(1/2)W^(-1),中波峰值探测率为6.7×10^(11)cm·Hz^(1/2)W^(-1),短中波有效像元率为99.51%,中波为99.13%,获得了高质量的成像效果,实现中中双色探测。

基于支持度变换和top-hat分解的双色中波红外图像融合

为了解决用多尺度top-hat分解法融合双色中波红外图像时经常存在对比度提升有限、边缘区域失真较重的问题,提出了基于支持度变换和top-hat分解相结合的融合方法。先用支持度变换法将双色中波图像分解为低频图像和支持度图像序列;再从最后一层低频图像中用多尺度top-hat分解法提取各自的亮信息和暗信息;用灰度值取大法分别融合亮信息和暗信息;通过灰度值归一化和高斯滤波分别增强亮、暗信息融合图像;然后融合两低频图像和亮、暗信息增强图像;将融合图像作为新的低频图像和用灰度值取大法融合得到的支持度融合图像序列进行支持度逆变换,得到最终融合图像。该方法的实验结果同采用单一的支持度变换法融合和多尺度top-hat分解法融合相比,融合图像的对比度提升了11.69%,失真度降低了63.42%,局部粗糙度提高了38.12%。说明提出的从低频图像提取亮暗信息,并经过分别融合、增强,再与低频图像进行融合,能有效破解红外融合图像对比度提升和边缘区域失真度降低之间的矛盾,为提高图像融合质量提供了新方法。

锑化物中/中波双色红外探测器研究进展

面对第三代红外探测器对多波段探测的需求,中/中波双色同时获取两个波段的目标信息,对复杂的背景进行抑制,可以有效排除干扰源的影响,提高了探测的准确性,增强了在人工及复杂背景干扰下的目标识别能力,因此中/中波双色探测器设计和制备最近快速发展起来。锑化铟红外探测器通过分光可实现两个中波波段的探测,锑化物Ⅱ类超晶格探测器通过能带结构设计实现多波段探测。本文阐述了锑化物中/中波双色红外探测器的主要技术路线和目前研究进展,与传统InSb双色探测器相比,中/中波双色超晶格红外器件用于红外成像探测具有鲜明的特点和优势,但需要在探测器结构设计、锑化物超晶格材料生长、阵列器件制备等方面进行进一步研究,以提高探测性能,满足工程化应用需求。

Application of dual color fluorescence in situ hybridiza tion (D-FISH) to the diagnosis of a 49, XXXXY chromo somal abnormality

To study the technique of D-FISH and its application in the diagnosis of a 49, XXXXY chromosomal abnormality. Methods: Biotin-labeled alpha satellite X chromosome DNA (pBamX7) probe and digoxi-genin-labeled Y chromosome long arm terminal repetitive sequence (pY3.4) probe in situ hybridized with pre-treated slides of peripheral blood chromosome and interphase nucleus. After washing, the slides were treated with avidin-FITC, rhodamine-FITC and anti-avidin, amplified with an additional layer and counter-stained with DAPI in an antifade solution. The hy bridization signals and chromosomal or interphase nucleus settings were observed respectively with WIB, WIG and WU filters under fluorescent microscope (Olympus AX-70) and the number of metaphase chromosome and interphase nucleus in the peripheral blood was counted. Results: The biotin-labeled pBamX7 probe showed 4 green hybridization signal and the digoxigenin-labeled pY3.4 probe showed 1 red hybridization signal. The chromosome or cytoplasm counter-stained with DAPI showed blue. The positive rate of X chromosome hybridization signal for the 350 metaphase chromosomes and interphase nucleus was 91.43 % and 92. 57 %, respectively, while that of the Y chromosome hybridization signal was 99.5 % and 99.8 %, respectively. Conclusion: D-FISH is a valuable technique in diagnosing 49, XXXXY chromosomal abnormality and other sex chromosomal abnormalities. [Reprod Contracep (in Chinese) 2002; 22: 287]

Gram-scale synthesis of all-inorganic perovskite quantum dots with high Mn substitution ratio and enhanced dual-color emission

Mn-doped all-inorganic perovskite quantum dots (QDs) provide prominent applications in the fields of low-cost light source or display,because of their remarkable properties including dual-color emission and reduced lead content,as well as high photoluminescence quantum yields (PLQYs) and high stability.However,the existing synthesis approaches usually require hash conditions,such as high temperature and nitrogen protection,which is a major hurdler for the practical manufacturing.In addition,the significantly high Mn substitution ratio in CsPbX3 QDs is still challenging.The real dual-color emission with two strong emission peaks in the Mn-doped all-inorganic perovskite QDs has attracted great interest.Here we present a gram-scale approach to synthesize both CsPbxMn1-xCI3 and CsPb1-xMnxClyBr3-y QDs at 100 ℃ in the air with high Mn substitution ratio,up to 55.64% atomically.The as-prepared CsPb1-xMnxClyBr3-y QDs exhibit high PLQYs of 62.41% and dual-color emission with two strong emission peaks around at 400-450 nm and 600 nm,respectively.The enhanced peak at 400-450 nm is a result of the hybrid halides in CsPbBrxCl3-x host.Furthermore,the unique advantage of the optical emission and high PLQYs properties of the CsPbxMn1-xCl3 QDs has been demonstrated as invisible ink for encryption applications and polymer composites.Our gram-scale synthesis approach for Mn-doped all-inorganic perovskite QDs may boost the future research and practical applications of QDs-based white LED,spintronics,and molecular barcoding.

Silicon carbide and graphene based UV-IR dual-color detector

An ultraviolet-infrared dual-color detector is proposed and realized based on the vertical integration of single-layer graphene and a 4 H-SiC layer by semiconductor micro-fabrication technology. The spectral response characteristics of the detector are analyzed. The ultraviolet response range is 208—356 nm with a responsivity larger than 0.4 mA/W and the infrared response range is 1.016—1.17 μm with a responsivity larger than 0.4 mA/W at room temperature and 5 V bias voltage. The peak responsivity of the graphene in the ultraviolet-C band at 232 nm is 0.73 mA/W and in the near infrared band at 1.148 μm is 0.64 mA/W. The peak responsivity of SiC layer in the ultraviolet-B band at 312 nm is 2.27 mA/W. Besides, the responsivity increases with the bias voltage.

Donor-conformation-dependent energy transfer for dual-color fluorescent probe with high-resolution imaging

Herein,we presented a brand-new concept to construct the Forster resonance energy transfer(FRET)based cassette by integrating a vibration-induced emission(VIE)chromophore as the donor.Different from traditional donors only with a single emission,the VIE donor possessed well-separated dual emission bands by altering the excited state molecular configuration from the bent state to the planar state.By linking an acceptor such as a cyanine dye(Cy5),a novel VIE-FRET cassette(PPCy5)was prepared.The planar emission profile of the VIE donor moiety could fully cover the absorption of Cy5,and thus the complete FRET process enabled the excellent bimodal spectra difference of 142 nm and ultra-large pseudo-Stokes shift of up to 300 nm.Benefiting from the viscosity-dependent characteristic of the VIE donor,PPCy5 could clearly and intuitively reveal the different viscosity regions in vivo by dual-color and high-resolution imaging.The VIE-FRET paradigm provides an optional platform for developing donor-acceptor-based dual-color fluorescent probes with high-resolution imaging ability.

Ultraviolet-infrared dual-color photodetector based on vertical GaN nanowire array and graphene

A monolithic integrated ultraviolet-infrared(UV-IR) dual-color photodetector based on graphene/GaN heterojunction was fabricated by vertically integrating a GaN nanowire array on a silicon substrate with monolayer graphene. The device detects UV and IR lights by different mechanisms. The UV detection is accomplished by the forbidden band absorption of GaN, and the IR detection is realized by the free electron absorption of graphene. At peak wavelengths of 360 nm and 1540 nm, the detector has responsivities up to 6.93 A/W and 0.11 A/W, detection efficiencies of 1.23 × 1012 cm·Hz1/2·W-1 and 1.88 × 1010 cm·Hz1/2·W-1, respectively,and a short response time of less than 3 ms.

A TICS-fluorophore based probe for dual-color GSH imaging

Cascading reactions in fluorophores accompanied by the replacement of different fluorescence wavelengths can be used to develop luminescent materials and reactive fluorescent probes.Based on multiple signal channels,the selectivity of probes can be improved and the range of response to guest molecule recognition can be expanded.By regulating the position,number,and activity of active sites in fluorophores,fluorescent probes that successively react with thiol and amino groups in cysteine(Cys),homocysteine(Hcy)have been developed,which can only react with the thiol group of GSH,In this paper,we report the first probe capable of cascading nucleophilic substitution reaction with the thiol group and amino group of GSH at a single reaction site,and showed the dual-color recognition of GSH,which improved the selectivity of GSH also was an extension of GSH probes.The probe Rho-DEA was based on a TICS fluorophore,and the intramolecular cascade nucleophilic substitution reaction occurs with Cys/Hcy.The thiol substitution of the first step reaction with Cys/Hcy was quenched due to intersystem crossing to triplet state,so GSH can be selectively recognized from the fluorescence signal.Rho-DEA has the ability of mitochondrial localization,and finally realized in situ dual-color fluorescence recognition of GSH in mitochondria.

Incubation and application of transgenic green fluorescent nude mice in visualization studies on glioma tissue remodeling

Background The primary reasons for local recurrence and therapeutic failure in the treatment of malignant gliomas are the invasion and interactions of tumor cells with surrounding normal brain cells. However, these tumor cells are hard to be visualized directly in histopathological preparations, or in experimental glioma models. Therefore, we developed an experimental human dual-color in vivo glioma model, which made tracking solitary invasive glioma cells possible, for the purpose of visualizing the interactions between red fluorescence labeled human glioma cells and host brain cells. This may offer references for further studying the roles of tumor microenvironment during glioma tissue remodeling. Methods Transgenic female C57BL/6 mice expressing enhanced green fluorescent protein （EGFP） were crossed with male Balb/c nude mice. Then sib mating was allowed to occur continuously in order to establish an inbred nude mice strain with 50% of their offspring that are EGFP positive. Human glioma cell lines U87-MG and SU3 were transfected with red fluorescent protein （RFP） gene, and a rat C6 glioma cell line was stained directly with CM-Dil, to establish three glioma cell lines emitting red fluorescence （SU3-RFP, U87-RFP, and C6-CM-Dil）. Red fluorescence tumor cells were inoculated via intra-cerebral injection into caudate nucleus of the EGFP nude mice. Tumor-bearing mice were sacrificed when their clinical symptoms appeared, and the whole brain was harvested and snap frozen for further analysis. Confocal laser scanning microscopy was performed to monitor the mutual interactions between tumor cells and host brain cells. Results Almost all the essential tissues of the established EGFP athymic Balb/c nude mice, except hair and erythrocytes, fluoresced green under excitation using a blue light-emitting flashlight with a central peak of 470 nm, approximately 50% of the offsprings were nu/nu EGFP＋. SU3-RFP, U87-RFP, and C6-CM-Dil almost 100% expressed red fluorescence under the fluorescence microscope. Under fluorescence microscopic view, RFP＋ cells were observed growing wherever they arrived at, locating in the brain parenchyma, ventricles, and para-vascular region. The interactions between the transplanted tumor cells and host adjacent cells could be classified into three types： （1） interweaving; （2） mergence; and （3） fusion. Interweaving was observed in the early stage of tumor remodeling, in which both transplantable tumor cells and host cells were observed scattered in the tumor invading and spreading area without organic connections. Mergence was defined as mutual interactions between tumor cells and host stroma during tumorigenesis. Direct cell fusion between transplantable tumor cells and host cells could be observed occasionally. Conclusions This study showed that self-established EGFP athymic nude mice offered the possibility of visualizing tumorigenesis of human xenograft tumor, and the dual-color xenograft glioma model was of considerable utility in studying the process of tumor remodeling. Based on this platform, mutual interactions between glioma cells and host tissues could be observed directly to further elucidate the development of tumor microenvironment.

Single-Molecular Co-localization Detection and Analysis

This talk will discuss single-molecule detection that shows on dual-color optical imaging data, image processing and statistical analysis can reliably differentiate random