Fabrication of large-area uniform carbon nanotube foams as near-critical-density targets for laser–plasma experiments
Pengjie Wang, Guijun Qi, Zhuo Pan, Defeng Kong, Yinren Shou, Jianbo Liu, Zhengxuan Cao, Zhusong Mei, Shirui Xu, Zhipeng Liu, Shiyou Chen, Ying Gao, Jiarui Zhao, and Wenjun Ma
Carbon nanotube foams (CNFs) have been successfully used as near-critical-density targets in the laser-driven acceleration of high-energy ions and electrons. Here we report the recent advances in the fabrication technique of such targets. With the further developed floating catalyst chemical vapor deposition (FCCVD) method, large-area ($>25\kern0.5em {\mathrm{cm}}^2$) and highly uniform CNFs are successfully deposited on nanometer-thin metal or plastic foils as double-layer targets. The density and thickness of the CNF can be controlled in the range of $1{-}13\kern0.5em \mathrm{mg}/{\mathrm{cm}}^3$ and $10{-}200\kern0.5em \mu \mathrm{m}$, respectively, by varying the synthesis parameters. The dependence of the target properties on the synthesis parameters and the details of the target characterization methods are presented for the first time.
  • Jun. 16, 2021
  • High Power Laser Science and Engineering
  • Vol.9 Issue, 2 02000e29 (2021)
  • DOI:10.1017/hpl.2021.18
Fabrication of disk-shaped, deuterated resorcinol/formaldehyde foam target for laser–plasma experiments
Yumi Kaneyasu, Keiji Nagai, Marilou Cadatal-Raduban, Daniil Golovin, Satoshi Shokita, Akifumi Yogo, Takahisa Jitsuno, Takayoshi Norimatsu, and Kohei Yamanoi
  • Jun. 16, 2021
  • High Power Laser Science and Engineering
  • Vol.9 Issue, 2 02000e31 (2021)
  • DOI:10.1017/hpl.2021.15
New phase-matching selection rule to generate angularly isolated harmonics
Xiaomei Zhang, Baifei Shen, Lingang Zhang, and Yin Shi
High harmonic generation (HHG) is an ideal probing source. In general, all harmonics are coupled with the corresponding input laser when generated, and for applications, they are separated using additional spectrometers. Herein, we report the angular isolation of relativistic harmonics at a predicted emission angle upon generation and, most importantly, a new phase-matching chain selection rule is derived to generate harmonics. Based on the laser plasma mechanism involving two non-collinear relativistic driving lasers, the nth harmonic carrying the information of both input lasers originates from its adjacent (n – 1)th harmonic coupled with one of the input lasers. Meanwhile, the intensity and emission angle of the generated isolated harmonic are both greatly increased compared with those in the gas scheme. These results are satisfactorily verified by theoretical analysis and three-dimensional particle-in-cell simulations, which have physical significance and are essential for practical applications.
  • Jun. 16, 2021
  • High Power Laser Science and Engineering
  • Vol.9 Issue, 2 02000e28 (2021)
  • DOI:10.1017/hpl.2021.14
[in Chinese]
LU Hong-Bo, LI Xin-Yi, LI Ge, ZHANG Wei, HU Shu-Hong, DAI Ning, and YANG Gui-Ting
Smaller Voc of 1.0 eV/0.75 eV InGaAsP/InGaAs double-junction solar cell(DJSC) than the Voc sum of individual subcells has been observed, and there is little information of the origin of such Voc loss and how to minimize it. In this paper, it is disclosed that the dominant mechanism of minority-carrier transport at back-surface-field(BSF)/base interface of the bottom subcell is thermionic emission, instead of defect-induced recombination, which is in contrast to previous reports. It also shows that both InP and InAlAs cannot prevent the zinc diffusion effectively. In addition, intermixing of major III-V element occurs as a result of increasing thermal treatment. To suppress the above negative effects, an initial novel InP/InAlAs superlattice(SL) BSF layer is then proposed and employed in bottom InGaAs subcell. The Voc of fabricated cells reach 997.5 mV, and a reduction of 30 mV in Voc loss without lost of Jsc, compared with the results of conventional InP BSF configuration, is achieved. It would benefit the overall Voc for further four-junction solar cells.现有1.0 eV/0.75 eV InGaAsP/InGaAs双结太阳电池的开路电压小于各子电池的开路电压之和,鲜有研究探索开路电压损耗的来源以及如何抑制。通过研究发现,InGaAs底电池背场/基区界面处的少数载流子输运的主要机制是热离子发射,而不是缺陷诱导复合。SIMS测试表明,采用InP或InAlAs背场均不能有效抑制Zn掺杂剂的扩散。此外,由于生长过程中持续的高温热处理,III-V族主元素在界面处发生了热扩散。为了抑制上述现象,提出了一种新型InP/InAlAs超晶格背场,并应用到InGaAs底电池中。制备得到的双结太阳电池在维持短路电流密度不变的情况下,开路电压提升到997.5 mV,与传统采用InP背场的双结太阳电池相比,开路电压损耗降低了30 mV。该研究成果对提升四结太阳电池的整体开路电压有重要意义。
  • Jun. 16, 2021
  • Journal of Infrared and Millimeter Waves
  • Vol.40 Issue, 1 2020115 (2021)
  • DOI:10.11972/j.issn.1001-9014.2021.01.002
[in Chinese]
XU Jie, XU Zheng-Bin, GUO Jian, QIAN Cheng, and ZHAO Di-Xian
This paper presents a millimeter-wave microstrip-based sub-harmonic mixer with a wide operation band. In this design, frequency suppression circuits including a wideband bandpass short-circuited filter and a diplexer are employed not only to provide proper terminations for the intermediate frequency (IF), radio frequency (RF), and local oscillator (LO) signals simultaneously, but also to reject the major idle mixing products. The measured results show that the proposed sub-harmonic mixer can support the operations in RF band from 27 to 48 GHz, and in IF band up to 6 GHz. Meanwhile, the conversion loss is less than 12.5 dB for both up- and down- conversion throughout the bandwidth, in which, the minimum conversion loss is about 7.5 dB and 8.2 dB for the down-conversion and up-conversion, respectively, at an RF of 33 GHz and IF of 1 GHz.设计了一款基于微带结构的宽带毫米波分谐波混频器。混频器中引入了短路结构的宽带射频滤波器以及一个高性能本振-中频双工器,这些无源电路能够抑制空闲组合频率,同时为中频、射频以及本振信号提供合适的回路。测试结果表明,本文设计的毫米波分谐波混频器射频工作频率为27~48 GHz,中频工作频率宽至6 GHz. 在整个工作频段内上、下变频损耗均小于12.5 dB。当射频为33 GHz,中频为1 GHz时,上变频、下变频达到最小变频损耗分别为8.2 dB和7.5 dB。
  • Jun. 16, 2021
  • Journal of Infrared and Millimeter Waves
  • Vol.40 Issue, 1 2020074 (2021)
  • DOI:10.11972/j.issn.1001-9014.2021.01.006
[in Chinese]
TIAN Yao-Ling, HUANG Kun, CEN Ji-Na, TANG Chuan-Yun, Lin Chang-Xing, and ZHANG Jian
The research on high power 110 GHz single and power-combined frequency doublers based on discrete diodes is presented in this paper. The doubler with a single Schottky diode circuit has a measured peak efficiency of 33% and bandwidth over 13.6%. Meanwhile, two different architectures with two single devices adding in-phase have been utilized to realize the power-combined doublers. The combined doubler features four discrete Schottky diodes with twelve junctions altogether soldered on two 127 μm-thick ALN substrates. Both devices have demonstrated output powers more than 200 mW with a pumping power over 800 mW and are capable of providing more power for higher driven power.研究了基于肖特基二极管的单路和功率合成式110 GHz大功率平衡式二倍频器。单路倍频器电路具有33%的峰值测试效率,且其工作带宽超过13.6%。另外,采用了不同的双路合成结构来实现两种不同的合成式110 GHz倍频器。该功率合成式倍频器在两只127 μm 厚的 ALN 基片上焊接了四个分立的肖特基二极管。在800 mW的驱动功率下,两种合成式倍频器都测得了大于200 mW的输出功率,证明了利用该合成式倍频结构可实现更高输出功率。
  • Jun. 16, 2021
  • Journal of Infrared and Millimeter Waves
  • Vol.40 Issue, 1 2020056 (2021)
  • DOI:10.11972/j.issn.1001-9014.2021.01.003
[in Chinese]
WANG Peng, YAO Hong-Yu, and ZHANG Gong
In this paper, a novel interpolation-based subpixel mapping (ISPM) for hyperspectral image by using pansharpening (PAN-ISPM) is proposed. In the proposed method, a novel processing path is added into the existing processing path of ISPM. Firstly, the original coarse hyperspectral image is improved by pansharpening technique in the novel processing path, and the novel fine fraction images are derived by unmixing the improved image. Secondly, the novel fine fraction images from the novel path and the existing fine fraction images from the existing path are integrated to produce the finer fraction images with more spatial-spectral information. Finally, according to the predicted values from the finer fraction images, class labels are allocated into subpixel to obtain the final mapping result. Experimental results show that the proposed method produces the higher mapping accuracy than the existing ISPM methods.利用全色锐化技术提出了一种新型基于插值的高光谱图像亚像元定位方法。在该方法中,在现有的基于插值的亚像元定位方法处理路径中加入一条新的处理路径。首先,在新的处理路径中利用全色锐化技术对原始粗高光谱图像的空间分辨率进行改进,通过对改进后的图像进行光谱解混得到新型精细丰度图像。其次,将新路径下产生的新型精细丰度图像与现有路径下的精细丰度图像进行融合,得到具有更多空间-光谱信息的更精细丰度图像。最后,根据更细分数图像的预测值,类别分配方法给每个亚像元分配类标签,得到最终的定位结果。实验结果表明,该方法比现有的基于插值的亚像元定位方法产生具有更高的定位精度。
  • Jun. 16, 2021
  • Journal of Infrared and Millimeter Waves
  • Vol.40 Issue, 1 2020052 (2021)
  • DOI:10.11972/j.issn.1001-9014.2021.01.010
Solid-state power amplifiers for space: going to extremely high frequency
YANG Fei, ZHAO Heng-Fei, LIU Jiang-Tao, LIU Rui-Zhu, LIU Yuan-Ping, HU Feng-Jiao, SUN Shu-Feng, YU Hong-Xi, and ZHOU Ying
Concentrating on the high frequency demands of solid-state power amplifier (SSPA) for space usage, the methodology and key techniques of the Q band 20 watts, V band 10 watts and W band 2 watts SSPAs are proposed in the present study. The GaN HEMT monolithic microwave integrated circuits (MMICs) are utilized as basic power amplifier units for power and efficiency enhancement. The high efficiency multi-ways low loss power combination techniques including magic T and radial-line were developed to achieve high output power. Copper diamond and heat pipes were applied to overcome heat dissipation and thermal flux challenges. By considering the strictly space qualification and components derating requirements, all products show state-of-art performances, which are used and verified in application for satellites payloads or terminal transmitters. To the authors knowledge, this is the first time the EHF band SSPA are developed and qualified for space usage in China. The designs proposed in the paper meet the demands and requirements for future satellite projects, to strongly support high frequency and high throughput space communication tendency and targets realization.
  • Jun. 16, 2021
  • Journal of Infrared and Millimeter Waves
  • Vol.40 Issue, 1 2020042 (2021)
  • DOI:10.11972/j.issn.1001-9014.2021.01.005
[in Chinese]
LI Miao, LIN Zai-Ping, FAN Jian-Peng, SHENG Wei-Dong, LI Jun, AN Wei, and LI Xin-Lei
Point target detection in Infrared Search and Track (IRST) is a challenging task. due to less information. Traditional methods based on hand-crafted features are hard to finish detection intelligently. A novel deep spatial-temporal convolution neural network is proposed to suppress background and detect point targets. The proposed method is realized based on fully convolution network. So input of arbitrary size can be put into the network and correspondingly-sized output can be obtained. In order to meet the requirement of real time for practical application, the factorized technique is adopted. 3D convolution is decomposed into 2D convolution and 1D convolution, and it leads to signi?cantly less computation. Multi-weighted loss function is designed according to the relation between prediction error and detection performance for point target. Number-balance weight and intensity-balance weight are introduced to deal with the imbalanced sample distribution and imbalanced error distribution. The experimental results show that the proposed method can effectively suppress background clutters, and detect point targets with less runtime.由于点目标可用信息少,点目标检测技术是红外搜索与跟踪系统(IRST)中的挑战性难点。基于人工提取特征的传统目标检测,智能化水平低,对点目标检测的难度大。针对此问题,提出一种新的2020011方法。该方法采用全卷积架构,输入输出尺度相同,可用于处理任意尺度图像。为了提高实时性,卷积分解技术被引入3D时空卷积处理中,将复杂3D时空卷积分解为低复杂度的2D空域卷积和1D时域卷积。根据点目标特点,多权值损失函数被提出,分别采用样本均衡因子和能量均衡因子降低样本不均衡和误差分布不均衡对点目标检测性能的影响。测试结果表明,该方法能够有效抑制复杂背景杂波,并以较低计算量实现点目标检测。
  • Jun. 16, 2021
  • Journal of Infrared and Millimeter Waves
  • Vol.40 Issue, 1 2020011 (2021)
  • DOI:10.11972/j.issn.1001-9014.2021.01.017
[in Chinese]
SHI Wen-Jun, WANG Deng-Wei, LIU Wan-Suo, and JIANG Da-Gang
A novel Graphics Processing Units (GPU) accelerated level set model which organically combines the global fitting energy and the local fitting energy from different models and the weighting coefficient of the global fitting term can be adaptively adjusted, is proposed to image segmentation. The proposed model can efficiently segment images with intensity inhomogeneity regardless of where the initial contour lies in the image. In its numerical implementation, an efficient numerical scheme called Lattice Boltzmann Method (LBM) is used to break the restrictions on time step. In addition, the proposed LBM is implemented by using a NVIDIA GPU to fully utilize the characteristics of LBM method with high parallelism. The extensive and promising experimental results from synthetic and real images demonstrate the effectiveness and efficiency of the proposed method.In addition, the factors that can have a key impact on segmentation performance are also analyzed in depth.面向图像分割应用,提出了一种新颖的GPU加速水平集模型,将来自于不同模型的全局及局部拟合能量有机地整合一起,并且可以自适应地调整全局项的加权系数。无论初始轮廓位于图像中的任何位置,模型都可以有效地分割出具有强度非同质性图像中的前景目标。在数值实现环节,采用格子玻尔兹曼方法的策略来打破传统求解方法对于时间步长参数的限制条件。另外,借助NVIDIA GPU来高效地组织格子玻尔兹曼方法的数值解算过程,以充分利用格子玻尔兹曼方法所具有的并行特性。在合成及真实图像数据上的实验结果验证了所提方法的有效性。另外,还对影响分割结果的数个关键因素进行了深入的分析。
  • Jun. 16, 2021
  • Journal of Infrared and Millimeter Waves
  • Vol.40 Issue, 1 2019343 (2021)
  • DOI:10.11972/j.issn.1001-9014.2021.01.016
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Special lssue

Special Issue on High Power Laser Science and Engineering 2021 (2021)

Submission Open:25 February 2021; Submission Deadline: 31 July 2021

Editor (s): Colin Danson, Jianqiang Zhu

Special Issue on XFELs (2021)

Submission Open:1 January 2021; Submission Deadline: 1 July 2021

Editor (s): Max Lederer, Haixiao Deng, Sergio Carbajo

Special Issue on 60th Celebration of First Laser (2020)

Submission Open:1 January 2020; Submission Deadline: 31 December 2020

Editor (s):