李琦

基本信息 科学研究 教育教学 论文专著 新建主栏目 基本信息 名称 李琦，女，汉族，1963年生。教授，博导；哈尔滨工业大学航天学院光电子信息科学与技术系、可调谐激光技术国家级重点实验室任职。 先后主持承担基金类等项目， 2013年获得关于太赫兹成像技术的国家自然科学基金面上基金1项。讲授研究生课程《光学图像数字化处理》多年，指导《现代光电子技术实验课》中光束整形实验，2012年起在本科生《光电子实验课》中负责两个实验。作为第一、二作者在国际SCI期刊发表论文30余篇，其中两篇太赫兹数字全息文章发表在Optics Letters上。 近几年，开始从事太赫兹超表面元件研究。 工作经历 名称 时间 工作经历 1987年9月-1994年8月 哈尔滨激光技术研究所工作 职称工程师 2000年1月至今 哈尔滨工业大学航天学院可调谐激光技术国家级重点实验室工作 教育经历 名称 1983年-1987年, 就读于哈尔滨科技大学, 应用物理系, 获得理学学士学位 1994年-1999年, 就读于哈尔滨工业大学, 电子科学与技术系，直攻博，获得工学博士学位 科研项目 项目名称 基于非相干量热测量的连续2.52THz数字全息成像机理研究 项目来源 教育部博士点基金 开始时间 2012-01-01 结束时间 2014-12-01 项目经费 12 担任角色 负责 项目类别 横向项目 项目状态 完成 简单介绍 项目名称 基于面阵探测器的连续太赫兹数字全息三维成像研究 项目来源 国家自然科学基金 开始时间 2014-01-01 结束时间 2017-12-01 项目经费 80 担任角色 负责 项目类别 横向项目 项目状态 完成 简单介绍 奖项成果 奖项名称 脉冲外差探测激光成像雷达技术研究 获奖时间 2010 完成人 王骐，李琦，田兆硕，陆威，孙剑峰 所获奖项 黑龙江省自然科学类科技进步三等奖 简单介绍 脉冲外差探测激光成像雷达技术研究主要进行了实验演示及图像处理等方面工作。 研究领域 名称 1. 太赫兹成像及其目标特性研究 2. 光束整形技术研究 主要研究方向:（1）材料的太赫兹目标特性测量研究；（2）太赫兹 数字全息特性研究；（3）实时太赫兹成像方法研究；（4）太赫兹传输特性研究；（5）光学图像数字化处理；（6）光束整形技术。 讲授课程 名称 《光学图像数字化处理》简介: 本课程为电子科学与技术学科硕士研究生选修课，主要介绍光学图像数字化处理的基本概念和基本理论，对光学图像的形成、噪声来源及其统计特征、一般二维图像预处理和图像跟踪等方法进行讲解，着重讲解三维图像的产生、预处理和自动识别等方法，并简单介绍光学图像数字化处理的硬件实现。本课程以真实的THz激光图像为例介绍图像处理作用，以真实的激光雷达所成的强度像为例，讨论散斑和散斑像的统计特性、给出散斑像的乘法模型；针对散斑噪声的强度像进行算法介绍。以真实的激光雷达所成的距离像为例，讨论噪声对距离像的影响、并介绍距离像处理算法。 招生信息 名称 硕士招生： 研究方向1：提高太赫兹数字全息成像质量研究 招收人数：1名 要求：光学和高等数学基础知识扎实且英语写作能力较强 研究方向2：太赫兹后向散射测量研究 招收人数：1名 要求：能较好的应用Matlab语言编程且高等数学基础知识较扎实 博士招生： 太赫兹三维成像技术研究 招收人数：1名 要求：光学和高等数学基础知识扎实且英语写作能力较强光束整形技术研究 招收人数：1名 要求：物理和高等数学基础知识扎实，能较好的应用Matlab语言编程 保障条件： （1）所有研究生（博士生和硕士生）均保证基本助研津贴，并根据实际工作成绩提高津贴。 （2）每人一台计算机。 （3）导师参与大部分真实实验。 （4）任何学生均可不拘泥于导师已定的研究方向，在开题前提出自己看好的新方向，跟导师讨论方案后确定是否更改研究方向。 （5）在校期间每周一次体育活动。 论文期刊 论文标题 Terahertz high-Q magnetic dipole resonance induced by coherent Fano interactions 作者 F. Yan, Q. Li, H. Hu, ZW. Wang, H. Tian, L. Li, Y. Luo, QJ. Wang, 发表时间 2022.11 期刊名称 Applied Physics Letters 期卷 121(20) 简单介绍 High Q-factor resonance holds great promise for bio-chemical sensing and enhanced light-matter interaction. However, terahertz (THz) magnetic resonances usually demonstrate low Q-factors, resulting in huge energy radiation loss particularly in high frequency bands. Here, we show that high Q-factor magnetic dipole resonance at THz frequencies can be achieved by exploiting the coherent Fano interactions with strong field enhancements in an array composed of single metallic split-ring resonators, working at Wood-Rayleigh anomalies. 论文标题 Broadband generation of abruptly autofocusing terahertz ring-Airy beams with all-silicon metasurface 作者 ZW. Wang , Q. Li , F. Yan 发表时间 2022.06 期刊名称 Optics & Laser Technology 期卷 150 简单介绍 Abruptly autofocusing terahertz (THz) ring-Airy beam has been generated by transmissive plasmonic metasurface at a single frequency in the earlier work. However, the transmission efffciency of it is low. Based on the waveguide effect, a design strategy for broadband generation of THz ring-Airy beams with transmissive allsilicon metasurface is proposed in this paper, which has an improved transmission efffciency and is more favorable in fabrication. Under the linearly polarized plane wave incidence, the amplitude and phase of the crosspolarized transmitted beam can be simultaneously modulated by controlling the rotation angles of the identical rectangular silicon pillars arranged on the silicon substrate. A polarization-independent antireffection square silicon pillar array is also proposed to be patterned at the other side of the substrate. The metasurface promises a working bandwidth from 2.12 to 2.72 THz with the overall transmission efffciency being over 51.18% (the highest transmission efffciency is up to 77.57% at 2.52 THz). The peak intensity positions of the generated beam during the propagation follow a parabolic trajectory. For the generated ring-Airy beam, the focal length is positively proportional to the frequency, while the abruptly autofocusing property and full width at half maximum (FWHM) of the focus are positively and negatively related with the frequency, respectively. This work can be expected to facilitate the applications of terahertz wave in biomedicine and manipulation of particles. 论文标题 Theoretical study on generation of radially polarized beam from linearly polarized beam with all-silicon metasurface in the terahertz regime 作者 ZW. Wang, Q. Li, F. Yan 发表时间 2021.04 期刊名称 Optics & Laser Technology 期卷 136 简单介绍 A transmissive all-silicon dielectric square metasurface with a side length of 12.4 mm is designed in this paper. At 2.52 terahertz, the normally incident x-polarized Gaussian beam can be shaped into the radially polarized narrow-width annular beam with Bessel-Gaussian amplitude distribution at a propagation distance of 45 mm away from the metasurface. 论文标题 Extremely high Q-factor terahertz metasurface using reconstructive coherent mode resonance 作者 F. Yan, Q. Li, ZW. Wang, H. Tian, L. Li 发表时间 2021.03 期刊名称 Optics Express 期卷 29(5) 简单介绍 The THz metasurface is composed of periodically arranged vertical symmetric split ring resonators (SRRs), which can produce perfect reconstructive coherent coupling effect in the sense that dipole radiation is destructively suppressed. Under the polarized electric field perpendicular to SRR gap, the surface currents are out of phase for an individual SRR, leading to the cancellation of net dipole moment. 论文标题 A high numerical aperture terahertz all-silicon metalens with sub-diffraction focus and long depth of focus 作者 WZ. Wang, Q. Li, F. Yan 发表时间 2021.02 期刊名称 J. Phys. D: Appl. Phys. 期卷 54(8) 简单介绍 A high numerical aperture (NA = 0.92) square all-silicon metalens is designed for a wavelength of lambda= 0.11883 mm with a focal length of 16.8 lambda and a side length of 104.4 lambda. 论文标题 An ultrahigh Q-factor dual-band terahertz perfect absorber with a dielectric grating slit waveguide for sensing 作者 F. Yan, Q. Li, H. Tian, ZW. Wang, L. Li 发表时间 2020.06 期刊名称 J. Phys. D: Appl. Phys. 期卷 53(23) 简单介绍 Full-wave simulation demonstrates that the proposed structure not only achieves ultra-narrow band perfect absorption with an ultrahigh Q-factor of 4600 in the THz regime, but it also shows extraordinary sensing performance with a record figure of merit (FOM) of 2415 at THz frequencies. 论文标题 Continuous-wave terahertz in-line digital holography 作者 K. Xue，Q. Li，Li, Yun-Da Li，Q. Wang 发表时间 2012.08 期刊名称 Optics Letters 期卷 37(15) 简单介绍 A terahertz (THz) in-line digital holography project has been proposed based on a CO2 pumped 2.52 THz continuous-wave laser and a pyroelectric-array camera used as the detector. The THz Gabor in-line digital holograms have been obtained and then the high resolution reconstruction of THz in-line digital holography was realized. The resolution of an in-line digital holography system has been tested by the use of a series of objects. High-quality and high-resolution reconstructed images have been obtained, and the real lateral resolution is higher than 0.2 mm. It can be inferred from the results that the THz Gabor in-line digital holography system has the abilities of real-time and high-resolution imaging. 论文标题 Continuous-Wave Terahertz Digital Holography by Use of a Pyroelectric Array Camera 作者 S. H. Ding, Q. Li, Y. D. Li, Q. Wang 发表时间 2011.06 期刊名称 Optics Letters 期卷 36(11) 简单介绍 Terahertz (THz) digital holography is realized based on a 2.52 THz far-IR gas laser and a commercial 124 x 124 pyroelectric array camera. Off-axis THz holograms are obtained by recording interference patterns between light passing through the sample and the reference wave. A numerical reconstruction process is performed to obtain the field distribution at the object surface. Different targets were imaged to test the system's imaging capability. Compared with THz focal plane images, the image quality of the reconstructed images are improved a lot. The results show that the system's imaging resolution can reach at least 0.4mm. The system also has the potential for real-time imaging application. This study confirms that digital holography is a promising technique for real-time, high-resolution THz imaging, which has extensive application prospects. 论文标题 Application of acquiring region of interest based on YOLOv5 model in terahertz digital holography[ 作者 KY. Cheng,Q. Li 发表时间 2023.05 期刊名称 Applied Optics 期卷 62(14) 简单介绍 The imaging process of terahertz in-line digital holography is susceptible to environmental interference, and it is difficult to obtain high-quality images and image segmentation results. The challenge can be better handled by using the region of interest (ROI) condition to improve the image quality of the object region and reduce the inter-ference of peripheral noise. In this paper, for two-dimensional 2.52 THz in-line digital holography, a method to add a variety of real backgrounds in the simulation scene is proposed, and through this method, a sufficient amount of close-to-real-scene images are produced to train the YOLOv5 model. 论文标题 深度学习用于连续太赫兹同轴数字全息重建 作者 成珂阳,李琦 发表时间 2023.10 期刊名称 中国激光 期卷 50(19) 简单介绍 研究两种将深度学习用于二维连续太赫兹同轴数字全息振幅重建的方法，并与传统的角谱法（ASM）和带切趾的振幅约束相位恢复算法（APRA）进行对比。第一种是端对端的U-net网络重建方法（H-UnetM），即网络输入图像为全息图；第二种是角谱法加U-net网络重建方法（AS-UnetM）。仿真研究表明，对于记录距离15～20 mm、分辨率0.3～0.5 mm目标的2.52 THz全息图，AS-UnetM重建优于APRA，而H-UnetM仅优于ASM但不如APRA。最后通过真实实验加以验证，结果表明H-UnetM能够重建目标，但部分背景噪声也被突出，而采用ASUnetM在目标附近的重建效果最佳。 论文标题 Experimental Research on Resolution Improvement in CW THz Digital Holography 作者 Qi Li, Sheng-Hui Ding, Yun-Da Li, Kai Xue, Qi Wang 发表时间 2012.04 期刊名称 Appl. Phys. B 期卷 107(1) 简单介绍 High-resolution continuous-wave terahertz (CW THz) real-time imaging operating at 2.52 THz is demonstrated based on THz digital holographic technique. To eliminate the influence of zero-order diffraction while reducing the recording distance, effective zero-order diffraction suppression methods are studied and compared. The spatial resolution of the imaging system is tested by imaging a self-made Siemens star. When the recording distance is 2.1 cm, the measured resolution can reach 0.245 mm. The experimental results confirm the high imaging performance of the THz digital holography system. 论文标题 Brewster’s angle method for absorption coefficient measurement of high-resistivity silicon based on CW THz laser 作者 S. Ding, Q. Li, R. Yao, Q. Wang 发表时间 2010.01 期刊名称 Appl. Phys. B 期卷 98(1) 简单介绍 A simple method for measuring the absorption coefficient of low absorbing materials using CW THz laser was put forward. The method was based on transmittance measurements at the Brewster's angle for p-polarized light, where the reflectance would be minimal, so interference caused by multiple reflections in the sample would be eliminated. Numerical simulations were carried out to evaluate errors in the proposed method. An experiment was also made to measure the absorption coefficient of high-resistivity Czochralski silicon at 118.83 mu m by the method. Based on CW THz laser, the method offers a convenient way to measure the material absorption coefficient and has a low cost, so it shows promising application prospects. 论文标题 Real-time, THz scanning imaging by use of a pyroelectric array camera and image denoising 作者 Q. Li, S. H. Ding, R. Yao, Q. Wang 发表时间 2010.11 期刊名称 J Opt. Soc. Am. A 期卷 27 (11) 简单介绍 A high-resolution large-area terahertz (THz) scanning imaging system is demonstrated based on a 124 x 124 pyroelectric array camera and a CO(2) pumped continuous-wave THz laser. By applying a scanning mechanism to the real-time imaging setup, images of large-area targets were accomplished. Self-made resolution charts were employed to test the resolution. In order to improve the image quality, the noise in the images was studied and modeled, and then the performance of several denoising methods was compared with real-time THz original images. The experimental results show that, with the help of anisotropic diffusion, noise can be effectively suppressed, and the results are visually pleasant even when there is great attenuation. Those results greatly confirm application potentials of THz imaging using pyroelectric cameras in the field of concealed object detection. 论文标题 High-Resolution Terahertz Reflective Imaging and Image Restoration 作者 S. H. Ding, Q. Li, R. Yao, Q. Wang 发表时间 2010.12 期刊名称 Appl. Opt. 期卷 49(36) 简单介绍 We present a high-resolution terahertz (THz) reflective imaging system, operating at 2: 52 THz, that employs a continuous-wave THz gas laser and a pyroelectric detector. The spatial resolution was evaluated from the system's modulation transfer function and tested by scanning a series of resolution targets. To further improve the image quality, Lucy-Richardson method was adopted to restore the scanning result. With the scanning spot profile measured using knife edge method, a satisfying restoration result can be obtained. Finally, the system's performance was observed by imaging some different test objects. 论文标题 Terahertz Computed Tomography Using A Continuous-Wave Gas Laser 作者 Qi Li, Yun-Da Li, Sheng-Hui Ding & Qi Wang 发表时间 2012.05 期刊名称 J Infrared Milli Terahz Waves 期卷 33 (5) 简单介绍 A 3D continuous-wave (CW) terahertz computed tomography (CT) system employing a gas laser operating at 2.52 THz is presented. With the 2D results the 3D images of the samples have been also obtained. The reconstruction results illustrate the promising application prospects of this CW THz CT system. 论文标题 Continuous-Wave Terahertz Scanning Image Resolution Analysis and Restoration 作者 Qi Li, Qiguo Yin, Rui Yao, Shenghui Ding, Qi Wang 发表时间 2010.03 期刊名称 Optical Engineering 期卷 49（3） 简单介绍 Resolution of continuous-wave (CW) terahertz scanning image is limited by many factors among which the aperture effect of finite focus diameter is very important. We have investigated the factors that affect terahertz (THz) image resolution in details through theory analysis and simulation. On the other hand, in order to enhance THz image resolution, Richardson-Lucy algorithm has been introduced as a promising approach to improve image details. By analyzing the imaging theory, it is proposed that intensity distribution function of actual THz laser focal spot can be approximatively used as point spread function (PSF) in the restoration algorithm. The focal spot image could be obtained by applying the pyroelectric camera, and mean filtering result of the focal spot image is used as the PSF. Simulation and experiment show that the algorithm implemented is comparatively effective. (C) 2010 Society of Photo-Optical Instrumentation Engineers. 论文标题 Experimental Research on THz Gabor Inline Digital Holography of Concealed Objects 作者 Qi Li, Kai Xue, Yun–Da Li, Qi Wang 发表时间 2012.10 期刊名称 Appl. Opt. 期卷 51(29) 简单介绍 Terahertz (THz) radiation has the characteristics of penetrating nonmetallic and nonpolar materials that are opaque to visible light, which makes THz digital holography have an application potential of imaging concealed objects with certain barriers. A CO2 pumped continuous THz Gabor inline digital holographic imaging system was utilized to conduct experimental researches on imaging concealed objects. Paper, Teflon, a plastic express envelope, and silicon wafers were used as barriers. High-quality reconstructed images were obtained. Compared with the reconstruction results without any barriers, the results verify the feasibility of THz Gabor inline digital holography in imaging concealed objects. 论文标题 Research on object-plane constraints and hologram expansion in phase retrieval algorithms for continuous-wave terahertz inline digital holography reconstruction 作者 Jq. Hu，Q. Li, ; SS. Cui, 发表时间 2014.10 期刊名称 Applied Optics 期卷 53(30) 简单介绍 n terahertz inline digital holography, zero-order diffraction light and conjugate images can cause the reconstructed image to be blurred. In this paper, three phase retrieval algorithms are applied to conduct reconstruction based on the same near-field diffraction propagation conditions and image-plane constraints. 论文标题 Arbitrary scanning of the Airy beams using additional phase grating with the cubic phase mask 作者 Xiao-Zhang Wang, Qi Li, and Qi Wang 发表时间 2012.10 期刊名称 Appl. Opt. 期卷 51(28) 简单介绍 To controllably deflect the Airy beam in a wide range dynamic, the method of combining the classical Airy cubic phase with a diffraction blazed grating phase was adopted in this paper. By dynamically adjusting the grating parameters, the transverse self-accelerating Airy beam allows arbitrary deflection, and the deflected position can be controlled precisely. The mathematical model of the Airy beam optical field distributions generated by the combined phase patterns were proposed to explain the feasibility. Its correctness was ultimately demonstrated by the experimental results. It is significant to use this method for the Airy beam deflection control in high-precision closed-loop aiming systems. 论文标题 Target Recognition of Ladar Range Image Using Even-Order of Zernike Moments 作者 Zheng-Jun Liu, Qi Li, Zhi-Wei Xia and Qi Wang 发表时间 2012.11 期刊名称 Appl. Opt. 期卷 51(31) 简单介绍 Ladar range images have attracted considerable attention in automatic target recognition fields. In this paper, Zernike moments (ZMs) are applied to classify the target of the range image from an arbitrary azimuth angle. However, ZMs suffer from high computational costs. To improve the performance of target recognition based on small samples, even-order ZMs with serial-parallel backpropagation neural networks (BPNNs) are applied to recognize the target of the range image. It is found that the rotation invariance and classified performance of the even-order ZMs are both better than for odd-order moments and for moments compressed by principal component analysis. The experimental results demonstrate that combining the even-order ZMs with serial-parallel BPNNs can significantly improve the recognition rate for small samples. 论文标题 Target Recognition of Ladar Range Image for Small Samples Using Classifier Ensembles 作者 Zheng-Jun Liu, Qi Li, Zhi-Wei Xia and Qi Wang 发表时间 2012.08 期刊名称 Optical Engineering 期卷 51(8) 简单介绍 The range image has received considerable attention in the automatic target recognition field; however, a mass of range images are generally difficult to be collected in a real application. Therefore, with small samples of laser radar (ladar) range images, classifier ensembles-support vector machine (SVM) ensembles and back propagation neural networks (BPNN) ensembles-are applied to improve the performance of target recognition in this paper. There are three aspects of experiments. 论文标题 Research on reconstruction algorithms in 2.52 THz Off–axis Digital Holography 作者 Qi Li, Sheng-Hui Ding, Yun-Da Li, Qi Wang 发表时间 2012.10 期刊名称 J Infrared Milli Terahz Waves 期卷 33 (10) 简单介绍 To eliminate the diffraction effect on Terahertz (THz) imaging and improve imaging system performance, digital holography has been investigated. The size of the common THz digital hologram and the recording distance are in the same order of magnitude, which does not satisfy the Fresnel approximation conditions. Meanwhile, diffraction has a great impact on free-space propagation behavior. So the research of the influence on reconstruction performance with different reconstruction algorithms is necessary. In this paper, the numerical simulations of the recording and reconstruction process of 2.52 THz off-axis digital holography imaging have been done, and the reconstruction performances of Fresnel angular spectrum algorithm, Rayleigh-Sommerfeld convolution algorithm and angular spectrum algorithm have been compared and analyzed as the reconstruction reference wave is different. The real experimental reconstruction results have also been presented.