近红外大数值孔径平场显微物镜设计

为满足飞秒激光微纳加工系统对高加工精度和大加工范围的需求，首先确定了该系统的重要组成部分-无限共轭距显微物镜所需具备的特性及设计指标。依据薄透镜组的初级像差理论，针对飞秒激光波长推导出光学系统为校正匹兹凡场曲和二级光谱所需满足的条件。该镜头由11片球面透镜构成，所选用材料皆为国产玻璃，同时避免三胶合结构的使用。设计了一套工作波长为785~815 nm，数值孔径为0.9，像方视场为22.5 mm，放大倍率为40的近红外平场复消色差显微物镜。设计结果表明:该镜头的MTF良好，全视场波像差均小于0.08，各种几何像差均远小于公差且满足平场和复消色差条件，能量集中度高。使用补偿器放松材料公差、加工公差和装调公差，公差分配后全视场RMS波像差小于0.09，满足实际应用要求。     

三分离式消热差制冷型中红外物镜的设计

为了满足多种复杂环境的使用需求,红外光学系统需要适应较大的工作温度范围。介绍了一种三分离式消色差消热差制冷型中红外物镜的设计方法。改进了三分离式结构物镜的孔径光阑位置,使物镜实现100%冷光阑效率,同时将这种结构与消热差模型相结合,推导出三分离式消热差物镜的初始光焦度分配关系,并给出透镜材料的组合原则。利用该方法设计了工作波段为3~5 m,焦距为88 mm,相对孔径为1:2的红外物镜,各视场弥散斑半径均小于5 m,调制传递函数MTF达到0.75@17 lp/mm,获得了很好的成像质量。该物镜在-20℃~+70℃温度范围内保持焦距、像面和像质很好的稳定,验证了三分离式消热差光学系统的设计方法。     

可见近红外宽波段复消色差高光谱物镜设计

为满足高光谱成像仪在365~1000 nm波段范围的成像需求,设计了一款中等视场角、大相对孔径的复消色差物镜。从初级色差理论出发,分析了可见近红外波段的玻璃材料的色散特性,为光学设计选择玻璃材料提供了理论依据。设计结果表明:通过对低色散氟冕玻璃的合理使用,物镜在宽波段内的色差得到了良好校正,二级光谱仅为0.014 mm。物镜焦距18 mm,相对孔径1∶2.4,视场角30°,成像质量接近衍射极限,满足高光谱成像仪的设计要求。     

近红外激光光斑功率密度时空分布探测器

光束质量是评价高能激光系统指标的重要参数,准确测量激光功率密度时空分布是获取激光光束质量、验证改进激光系统设计及实际应用的重要依据.介绍了一种采用光电探测器阵列实现近红外波段高能激光束功率密度时空分布的测量方法,可实现波长范围为0.9～1.7μm、功率密度为mW/cm2～kW/cm2量级的激光光斑参数测量,并具有探测光...     

红外焦平面器件对不同波长激光辐照的响应特性研究

为了有效地干扰红外焦平面探测器,需要研究在不同波长激光的辐照下该探测器的响应情况。本文采用四种波长的激光进行辐照实验。研究结果表明,探测器像元很容易达到饱和状态,器件的响应与光谱响应曲线基本吻合。结果验证了干扰效果与光谱响应曲线之间的关系,为中红外激光干扰提供了实验依据。最后对红外焦平面器件对波段内激光的响应机制进行了简要分析。     

大口径宽光谱折射平行光管系统设计

介绍了大口径、宽光谱、折射式平行光管物镜的设计理论。结合项目设计实例：工作波长范围400nm~1100nm,焦距2000mm,相对口径1/10的折射式平行光管系统,论述了光学设计初期玻璃材料选取、初始结构选取与光焦度分配等问题。利用修正的相对部分色散P与阿贝数V建立复消色差方程组求解初始结构,使用Zemax软件优化设计出在全谱段范围内复消色差的平行光管系统。最后,给出Zemax软件分析的像差结果,系统中心视场内的点列图优于5μm ,中心波长波像差优于1/60λ,焦距色偏移量为0.33mm,其余像差均在设计指标之内。     

红外折/衍混合光学系统无热化设计

论述了利用衍射元件实现光学系统消热差的原理和设计方法.利用衍射光学元件特殊的消热差和消色差特性,设计了8～12μm波段内,焦距为90mm,F/#为1.5,视场角为±2°,在-40～80℃温度范围内既消热差又消色差的折/衍混合红外光学系统,并给出了评价结果.该系统在工作温度范围内,成像质量接近衍射极限,适用于非制冷红外焦平面阵列热像仪上.     

大相对口径长焦距折射式光学系统设计

分析了大相对孔径、长焦距折射式光学系统的像差特点,针对一款口径300mm,焦距540mm,波段范围500~850 nm,视场角2的折射式成像物镜进行了设计。首先根据系统的像差特点,针对二级光谱,选择了Petzval 型作为初始结构,并进行了复杂化,形成大空气间隔的三组元形式,利于像差的校正和后组元件尺寸的减小;而后针对使用波段对玻璃材料的部分色散P 和阿贝数V 值进行了修正,并绘制了P-V 图,从中选择了具有一定二级光谱校正能力并性能优良的玻璃材料。最终系统的二级光谱达到了0.06 mm,表明具有较好的复消色差性能。设计结果系统在相机Nyquist 频率(39 lp/mm)处各视场MTF 大于0.8,80%能量集中在直径为8 m 的圆内,小于一个象元尺寸,最大畸变小于0.1%,各项指标均满足设计要求。     

带对准光路的激光细胞穿孔显微物镜设计

针对近红外光谱可对活体组织进行无损伤穿孔,并解决在穿孔中需要重新对焦的问题,通过Zemax软件对7片式前置光阑显微物镜结构在0.48~1.48?m波长范围内进行了宽光谱消色差的优化设计。设计实现了像距为无限远的多光谱共焦成像,其放大倍率为40,数值孔径0.5,最大焦面漂移量仅为27?m,可见光波段在空间频率为350 lp/mm时,0.7视场的MTF>0.5,具有较高的分辨力。并且在波长1480 nm处,MTF值接近衍射极限,具有较高的能量,满足细胞穿孔的要求。文中还给出了实验结果,并预测其应用前景。     

CO2激光雕刻机的折/衍混杂f-θ镜设计

以工作于CO2激光主波长的传统两片球面透镜型f-θ镜为基础,引入衍射面实现消色差,设计了工作于可调谐CO2激光的波段范围9.0～11.0 μm的f-θ镜.结果表明,所设计的折/衍混杂f-θ镜不仅很好地工作在所要求的波段范围内,而且单色像差比原单波长f-θ镜有所提高,像面上的光斑在各个波长和视场上大小均匀.系统像差在各个波长上都接近或达到衍射极限,具有精确的光学扫描特性.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Call for Papers

正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its