多变视场的多焦点多光子激发荧光显微技术

发展了一种新型的多焦点多光子激发荧光显微技术,通过软件控制空间光调制器,在所需要的成像区域产生相应的激发光点阵,通过扫描入射角实现激发点阵快速并行扫描激发,通过CCD并行记录所产生的荧光信号,获得任意视场图像。分别实现了10×10和50×50点阵激发下的全视场双光子荧光图像,并且实现了同时多个区域寻址的多焦点激发成像。对比其他多焦点显微技术,该技术具有明显的灵活性,不但保持了多焦点激发的快速成像的优点,而且还增加了任意数量成像区域同时寻址和阵列点密度变化,所有这些变化只需要通过软件加载相应的相位图案给空间光调制器,而不需要任何硬件更改。     

Parallel Raman microspectroscopy using programmable multipoint illumination

We present a novel parallel Raman microspectroscopy scheme for simultaneously collecting Raman spectra from multiple points. This scheme is realized by projectinga multiple-point laser illumination pattern using a spatial light modulator (SLM) and wide-field Raman imaging collection. We demonstrate the performance of this scheme using uniform samples, trapped polymer microparticles and fixed polymer microparticles with mixed molecular composition within a 50×50 μm(2) field of view. This scheme enables the acquisition of Raman spectra from as many as 40 points simultaneously using a single illumination pattern and detector recording frame without scanning.     

Optical Implementation of CMOS/SEED Optoelectronic Integrated Crossbar Interconnection Network

１　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ａｓ“ｗｉｒｅｉｎｔｅｒｃｏｎｎｅｃｔｉｏｎ”ｏｆｅｌｅｃｔｒｏｎｉｃｃｏｍｐｕｔｅｒｈａｓｓｏｍｅｓｈｏｒｔａｇｅｓｓｕｃｈａｓｂｏｔｔｌｅｎｅｃｋ,ｃｌｏｃｋｓｋｅｗ,ＲＣｃｏｎｓｔａｎｔ,ｌｉｍｉｔｅｄｔｉｍｅｓｐａｃｅｐｒｏｄｕｃｔ,ｃｒｏｓｓｔａｌｋ,ｉｔｉｓｄｉｆｆｉｃｕｌｔｔｏｆｕｒｔｈｅｒｉｍｐｒｏｖｅｔｈｅｐｅｒｆｏｒｍａｎｃｅｏｆｅｌｅｃｔｒｏｎｉｃｉｎｔｅｒｃｏｎｎｅｃｔｉｏｎｎｅｔｗｏｒｋ．Ａｓｌｉｇｈｔｗａｖｅｈａｓｔｈｅｆｅａｔｕｒｅ…     

Optical Implementation of CMOS/SEED Optoelectronic Integrated Crossbar Interconnection Network

An optical implementation of CMOS/SEED optoelectronic integrated crossbar interconnection network is reported. The CMOS/SEED smart pixel arrays with O/E light windows are used as logical controlling switch nodes. High/lower modulating ratio of the output light density is about 1.4. The light beam is supplied by a 0.85 μm semiconductor laser diode. 8×2 spot arrays formed by a computer-generated phase grating are used as the pumping light beams for CMOS/SEED light modulators. High-precision 2-D optical fiber bundle arrays are used as the I/O access devices. 16×16 optical crossbar interconnection network is realized using our experimental setup. It is easy to couple with CMOS/SEED smart pixel arrays by using 2-D optical fiber bundle arrays as the I/O access devices. Compact in comparison with other optical interconnection systems.     

Stroboscopic supercontinuum white-light interferometer for MEMS characterization

We used a supercontinuum-based scanning white-light interferometer to characterize the oscillation of a MEMS device. The output of a commercially available supercontinuum light source (FiberWare Ilum II USB) was modulated to achieve stroboscopic operation. By synchronizing the modulation frequency of the source to the sample oscillation, dynamic 3-D profile measurements were recorded. These results were validated against those obtained with a white light LED setup. The measured maximum deflection of a 400×25×4 μm(3) microbridge driven with 0-6.8 V sinusoidal voltage at 10 Hz was 1.42±0.03 μm (supercontinuum), which agreed with the LED measurement. The method shows promise for characterization of high-frequency MEMS devices.     

Simultaneous compensation for spatial and temporal dispersion of acousto-optical deflectors for two-dimensional scanning with a single prism

The dispersive nature of the acousto-optical deflector (AOD) presents a challenge to applications of two sequential orthogonal AODs (a two-dimensional AOD) as XY scanners in multiphoton microscopy. Introducing a prism before the two-dimensional (2D) AOD allows both temporal and spatial dispersion to be compensated for simultaneously. A 90 fs laser pulse was broadened to 572 fs without compensation, and 143 fs with compensation. The ratio of long axis to short axis of the exiting laser beam spot was 3.50 without compensation and 1.14 with compensation. The insertion loss was 37%. Two-photon fluorescence microscopy used the compensated 2D AOD scanner to image a fluorescent microsphere, which improves signal intensity -15-fold compared with the uncompensated scanner.     

可见光/长波红外共聚焦窗口望远物镜设计

双波段/多波段融合成像技术受到普遍重视,使得双波段光学系统尤其是可见光/长波红外(VIS/LWIR)成像系统成为研究的重要方向之一。在分析反射式、折反式和折射式双波段成像系统的结构形式以及常用的折射共窗口系统的组成和特点的基础上,针对双波段系统在应用中的欠缺,设计了一款可用于手持式设备的VIS/LWIR共窗口折射望远系统,系统的主要技术指标为:0.6～0.8μm(VIS),8～12μm(LWIR),f′VIS=47 mm,f′IR=58mm,2ω=9.8°,FVIS=2,FIR=1.3。设计结果符合各项指标,像质在两个波段均满足使用要求。整个光学系统尺寸为51mm×93mm×136mm,结构紧凑,实用性强。     

平行排列液晶器件的波前调制特性

设计了一种新型的平行排列液晶相位调制器(LC PM),可在纯相位的模式下进行相位调制,研究了液晶相位调制器的光学特性,理论上给予了分析．对畸变波前进行了调制,在1 cm2的校正面积上,调制后的准确度PV(peak to valley)值接近λ／15(λ=0.6328 μm),RMS(Root Means Square)可达到λ／100,斯特列尔比SR (Strehl Ratio)达到0.989．改变了传统的扭曲向列液晶器件难于进行纯相位调制和得到高准确度调制的缺点,达到了理想的效果.     

利用莫尔条纹测量物体三维形貌新方法研究

提出了以计算机控制光栅产生莫尔条纹来测量物体三维形貌的新方法.利用计算机控制空间光调制器（Space Light Modulator,SLM）产生可控制幅度及位相的理想光栅,将平行光波投影到待测物体上,其反射光通过参考光栅形成莫尔条纹,利用CCD接收并进行数字图像处理,恢复出待测物体的三维形貌.对此方法进行了理论分析,推导了变形莫尔条纹与待测物形貌变化的关系式.利用MATLAB对此关系式进行仿真计算,其准确度可达0.011 μm.     

全息光盘存储器的数据存取与像素匹配

全息光盘存储(HDS)技术作为一种非常具有潜力的新型信息存储技术, 是下一代光盘发展的目标。在全息光盘存储系统中, 为了实现数据精确快速地写入和读出, 降低误码率, 需要在整个高分辨率页面上实现空间光调制器(SLM)与光电阵列耦合器(CCD)之间1∶1像素匹配。在体全息存储理论和光学设计理论基础上, 研究实现SLM和CCD像素1∶1匹配的方法, 提出了实现像素匹配的要求和条件, 并且按照此要求完成该全息光盘存储器的光学系统。实验中, 分别使用随机数据掩膜版和SLM实现了对CCD的512×512精确像素匹配, 在光学系统中引入存储介质条件下, 图像质量良好, 掩膜版和SLM原始误码率分别为2.5×10-4和1.5×10-4。     

Optical-feedback cavity-enhanced absorption spectroscopy with a quantum cascade laser

Optical-feedback cavity-enhanced absorption spectroscopy is demonstrated in the mid-IR by using a quantum cascade laser (emitting at 4.46 μm). The laser linewidth reduction and frequency locking by selective optical feedback from the resonant cavity field turns out to be particularly advantageous in this spectral range: It allows strong cavity transmission, which compensates for low light sensitivity, especially when using room-temperature detectors. We obtain a noise equivalent absorption coefficient of 3 × 10(-9)/cm for 1 s averaging of spectra composed by 100 independent points. At 4.46 μm, this yields a detection limit of 35 parts in 10(12) by volume for N(2)O at 50 mbar, corresponding to 4 × 10(7) molecules/cm(3), or still to 1 fmol in the sample volume.     

Two-dimensional light confinement in cross-index-modulation plasmonic waveguides

We report a numerical study of plasmonic waveguides that localize light in two dimensions at a cross section of 4.2 nm × 2.1 nm with the propagation length of 38 μm. By varying the geometrical parameters, strong mode confinements (range from λ(2)/3352 to λ(2)/2557525) are achieved with controllable propagation distance (44.68-40.988 μm), and mode size below 1 nm(2) has been demonstrated for the first time. Furthermore, a cross-index-modulation mechanism is proposed to explain the strong field localization behavior, providing guidelines for future waveguide designs.     

Ultrahigh-resolution full-field optical coherence tomography using spatial coherence gating and quasi-monochromatic illumination

We developed an ultrahigh-resolution full-field optical coherence tomography (FF-OCT) microscope that is based on the spatial, rather than the temporal, coherence gating. The microscope is capable of observing three-dimensional microbiological structures as small as 0.4 μm × 0.4 μm × 1.0 μm (xyz) using quasi-monochromatic light and a liquid crystal retarder. Unlike traditional FF-OCT systems, this microscope can be operated in high resolution for any preferable wavelength with minimized defocusing and dispersion effects. High-resolution images of an onion cell are presented.     

Use of a lensed fiber for a large-field-of-view, high-resolution, fiber-scanning microendoscope

We report the application of a lensed fiber to a miniaturized fiber raster scanner in order to reduce the fiber's output beam size, thereby allowing for a compact and flexible endoscope capable of a large field of view (FOV) and high spatial resolution. For a proof of principle, the fabricated lensed fiber scanner is paired with a miniaturized gradient-index assembly to achieve a one-photon lateral resolution of 1.1 μm with a FOV that has a diameter of 440 μm.     

一种双波段成像系统的红外通道杂散光分析

为全面分析杂散光对红外系统成像质量的影响,设计了可见波段0.4 μm~0.7 μm、红外波段3 μm~5 μm,视场角均为2.27°×2.27°的共孔径成像光学系统。分析了杂散光来源,分别研究了带内与带外杂散光对其红外通道成像质量的影响。对于带内杂散光,设计了消杂光结构,采用FRED软件模拟分析了带内杂光抑制能力,结果表明:带内杂散光得到较好抑制,其鬼像影响可忽略不计,太阳杂散光抑制水平PST达到设定的10-8阈值量级。对于带外杂散光,主要研究了1.064 μm和2.6 μm两个波长带外激光对红外成像系统的影响,并利用有限元仿真计算,结果表明:系统反射镜温升达到703 K时,向外发出较强带内红外辐射,到达像面的辐射功率为0.195 mW,可对红外成像面造成强烈噪声干扰。     

多光谱共孔径无穷远目标器设计

为实现场外车载光电跟踪仪的各光轴一致性检校,提出一种利用多光谱共孔径无穷远目标器、转光管和移动机构来实现对各光轴检校的方法,并对目标器进行了光学设计和总体结构设计,对影响检校的主要误差进行了分析。目标器总体尺寸为750 mm×120 mm×100 mm,采用离轴双曲面反射式光学系统,焦距为1 200 mm,孔径为50 mm,视场2°,分划板采用ZnS材料,光源采用溴钨灯,利用Zemax光学设计软件优化系统,实现焦面最大弥散斑为RMS 35.766 μm, 在空间频率5 lp/mm处,OTF均高于0.3,各项指标满足检校要求。     

随机扫描多光子荧光显微成像系统

多光子荧光显微成像是生物学研究的有力手段,但目前的成像速度难以满足神经成像中快事件检测的需要。针对这一问题,提出了一套随机扫描快速多光子荧光显微成像系统。系统采用二维声光偏转器快速扫描飞秒激发光束,能够以每点10μs的速度对特定的感兴趣区域进行跳跃式扫描,即随机扫描,使得有效的扫描速度大为提高。引入单棱镜补偿方法解决应用声光偏转器带来的色散问题。以170 nm荧光小球为样品,测得系统的横向分辨力为0.3μm,纵向分辨力为1.3μm。给出了随机扫描系统和商品化多光子荧光显微镜对同一个荧光细胞的成像结果,证明了新系统的成像能力。     

波导适用型铝锗酸盐玻璃中铥离子上转换荧光光子输出与量子产率定量

制备了适用于钾钠离子交换波导的Tm~(3+)/Yb~(3+)掺杂铝锗酸盐玻璃,利用积分球配以光纤光谱仪在975nm激光泵浦下对玻璃的上转换荧光进行测试,解析出样品的绝对荧光特征参量。测试与计算结果显示,在380℃的KNO3熔盐中,Tm~(3+)/Yb~(3+)掺杂的铝锗酸盐玻璃的钾钠离子交换有效扩散系数为0.070μm~2/min,热离子交换过程易于控制。铝锗酸盐玻璃样品中,Tm~(3+)主要发出477 nm蓝光和806 nm近红外光,其中近红外光为支配性发射。绝对荧光参数和激发功率密度呈正相关,当功率密度达到1 482 W/cm2时,三光子上转换蓝光的绝对光谱功率、净发射光子数和量子产率分别为269μW、6.46×10~(14)/s和1.43×10~(-4),双光子近红外光上转换对应的3个参量分别为4 024μW、1.63×10~(16)/s和3.61×10~(-3)。基于波导适用型铝锗酸盐玻璃中Tm~(3+)上转换荧光的绝对化表征,为进一步研发光电子器件和激光材料提供了有益的数据参考。     

基于软光刻的多层光互连垂直耦合结构

设计并试制了一种新型垂直耦合光互连线路结构,可用于高速计算机内部等垂直堆叠的多层连通光互连的芯片间光信息通讯。其结构简单,且具有较小的连接损耗(可低至0.05dB)。对四种不同的典型波导截面(分别为30μm×30μm,50μm×50μm,100μm×100μm,200μm×200μm),利用蒙特卡罗多光线追迹分析法对跨越1~6层的垂直耦合结构进行了性能分析,发现当该结构的跨越高度与横向跨越距离的比值约为0.128时,可实现较理想的低损耗(低于1dB)光传输。采用软光刻的方法制备了实验多层光互连线路,其性能测试与理论结果基本相符。     

镁敏化美他环素荧光显微成像技术应用于北京市密云县养殖场生鲜乳抗生素残留量的检测

采用抗生素治疗奶牛乳腺炎是目前普遍采用的一种方法,因此牛奶中抗生素残留问题倍受国际社会关注。寻求简便可行、灵敏度高的检测技术,以适用日趋严格的残留限量要求,保障人们安全、卫生地饮用牛奶至关重要、迫在眉睫。基于固载表面溶剂毛细流的自组装环效应,采用镁敏化美他环素荧光显微成像技术检测了北京市密云县4家养殖场生鲜乳中美他环素残留量,建立了一种检测新方法。实验表明,在pH9.99NH3-NH4Cl缓冲溶液及聚乙烯醇-124存在下,镁和美他环素能形成较强荧光的1∶1配合物,并在憎水性玻片表面形成自组装环,环直径0.93mm,环线宽26.2μm。当点样体积为0.50μL时,线性范围为2.2×10-13～3.6×10-12mol.ring-1(4.4×10-7～7.2×10-6mol.L-1),检测限(3σ)为8.8×10-14mol.ring-1(1.8×10-7mol.L-1)。应用于生鲜牛奶样品中抗生素的检测,得到了满意结果,回收率为93.8%～108%,RSD小于4.3%。