Journals >Journal of Infrared and Millimeter Waves
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2020
Volume: 39 Issue 1
14 Article(s)
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Infrared Spectroscopy and Spectral Analysis
Cheng-Kun WANG, and Peng ZHAO
Wood is usually stored outdoors so that when its hyper-spectral image is picked up, the acquired image is usually disturbed by environmental factors such as illumination, temperature, and humidity. This disturbance may produce the false wood species classification results. To solve this issue, the wood texture feature Wood is usually stored outdoors so that when its hyper-spectral image is picked up, the acquired image is usually disturbed by environmental factors such as illumination, temperature, and humidity. This disturbance may produce the false wood species classification results. To solve this issue, the wood texture feature is extracted in its hyper-spectral image by use of PLS and LBP. This texture feature is then combined with the near infrared spectra of wood hyper-spectral image so that the fused features are sent into SVM and BP neural network classifiers. Experimental results indicate that our scheme can reach to 100% classification accuracy without environmental disturbance. Moreover, to testify our scheme’s robustness in case of illumination variation, a simulation experiment is performed and it indicates that our scheme outperforms the conventional and the state-of-art wood recognition schemes..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 20, 2020
- Vol. 39, Issue 1, 72 (2020)
Shao-Jing SONG, Yu-Wei CHEN, Hai-Jiang HU, Jin-Yan HU, Yu-Mei GONG, and Hui SHAO
In the autonomous driving system of automobile, in order to improve the performance of single-wavelength LIDAR in physical property detection classification and state, and draw lessons from the principle that multi-spectral detection has physical property detection ability, this paper studies the band selection of multIn the autonomous driving system of automobile, in order to improve the performance of single-wavelength LIDAR in physical property detection classification and state, and draw lessons from the principle that multi-spectral detection has physical property detection ability, this paper studies the band selection of multi-spectral LIDAR, calculates and analyses the spectrum of typical targets in autonomous driving by using principal component analysis method. The characteristics of laser source and detector, the band selection method of multi-spectral LIDAR, the spectral characteristic analysis of typical targets for autonomous driving application scenarios and the availability of commercial LIDAR are synthesized. The central wavelength of the multi-spectral LIDAR suitable for autonomous driving of automobiles is 808 nm, 905 nm, 1 064 nm and 1 310 nm. The validity of the selected wavelength of the multi-spectral LIDAR is verified by testing. .
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 20, 2020
- Vol. 39, Issue 1, 86 (2020)
Su-Yu MA, Chuan-He MA, Xiao-Shuang LU, Guo-Shuai LI, Lin SUN, Ye CHEN, Fang-Yu YUE, and Jun-Hao CHU
The bandedge electronic structure including the optical bandgap, band-tail states, and deep/shallow donor and acceptor levels in Cu2ZnSnS4 semiconductor was analyzed by absorption, photocurrent and photoluminescence spectroscopy, and the theoretical reports. It is revealed that the SnZn-related defect in Cu2ZnSnS4 withThe bandedge electronic structure including the optical bandgap, band-tail states, and deep/shallow donor and acceptor levels in Cu2ZnSnS4 semiconductor was analyzed by absorption, photocurrent and photoluminescence spectroscopy, and the theoretical reports. It is revealed that the ![]()
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Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 20, 2020
- Vol. 39, Issue 1, 92 (2020)
Materials and Devices
Yu-Shun CHENG, Hui-Jun GUO, Hao LI, Lu CHEN, Chun LIN, and Li HE
HgCdTe avalanche photodiodes （APDs） of linear mode have attracted much attention for their prospective applications, due to the lowest excess noise close to zero, operating bias in the range of -12~0V, and linear gain tunable as well. In this paper, we investigated the dark current mechanism and Okuto-Crowell model basHgCdTe avalanche photodiodes （APDs） of linear mode have attracted much attention for their prospective applications, due to the lowest excess noise close to zero, operating bias in the range of -12~0V, and linear gain tunable as well. In this paper, we investigated the dark current mechanism and Okuto-Crowell model based on the PIN structure of mid-wave infrared HgCdTe e-APD. The characteristics of dark current and the gain were simulated. The thickness and carriers concentration of intrinsic region were discussed, which would impact on the dark current and the gain. The results indicated that the peak intensity of electric field would significantly increase the band to band generation, even up to several orders of magnitude. BBT current could be suppressed by increasing the thickness of the intrinsic region, as well as reducing the carrier concentration. Unfortunately, the gain and BBT current would both increase with electric field. The gain normalized dark current （GNDC） is prospective by means of tradeoff between the dark current and the gain. In our studies, intrinsic region with 3 μm and the concentration less than 5×1014cm-3 are optimal. The APD I-V results demonstrated that the theoretical model was identical with the experimental data..
Journal of Infrared and Millimeter Waves
- Publication Date: Mar. 12, 2020
- Vol. 39, Issue 1, 6 (2020)
Hai-Sha NIU, Ming-Xin YU, Bo-Fei ZHU, Qi-Feng YAO, Qian-Kun ZHANG, Li-Dan LU, Guo-Shun ZHONG, and Lian-Qing ZHU
The photonic artificial intelligent chip performs calculations at the speed of light, and has the advantages of low power consumption, low delay, and anti-electromagnetic interference. Miniaturization and integration are the key steps to realize this technological innovation. In this paper, lithography is applied to thThe photonic artificial intelligent chip performs calculations at the speed of light, and has the advantages of low power consumption, low delay, and anti-electromagnetic interference. Miniaturization and integration are the key steps to realize this technological innovation. In this paper, lithography is applied to the fabrication of diffraction gratings. A design and implementation method of all-optics diffraction deep learning neural network grating based on 10.6 micron laser is proposed. Since the wavelength of the light source evolved from the millimeter wave to micrometer wave, the characteristic scale of the neuron are reduced to 20 micrometers. Compared with the existing optical computing neural network, the feature size of the deep learning neural network is reduced by 80 times, which laid the foundation for further large-scale integration of photonic computing chips..
Journal of Infrared and Millimeter Waves
- Publication Date: Mar. 12, 2020
- Vol. 39, Issue 1, 13 (2020)
Ying HAN, Ting-Ting DONG, Yuan QING, Peng SONG, Wei-Zhen ZHU, Fan-Di ZHOU, Zheng-Ran LI, Wei WANG, and Lan-Tian HOU
A hollow-core anti-resonant fiber is proposed with low confinement loss in infrared band. The cladding tube is a semicircular semi-elliptical splicing structure. The full vector finite element method is used for the simulation. The semi-minor axis of the semi-elliptical tube is equal to the radius of the semicircular tA hollow-core anti-resonant fiber is proposed with low confinement loss in infrared band. The cladding tube is a semicircular semi-elliptical splicing structure. The full vector finite element method is used for the simulation. The semi-minor axis of the semi-elliptical tube is equal to the radius of the semicircular tube. A semi-circular tube and a semi-elliptical tube are spliced to form a semi-circular semi-elliptical cladding tube. The negative curvature and the positive curvature are changed by improving the structure parameters of the tube. The purpose of this paper is to study the loss characteristics of the positive and negative curvature of the cladding tube, and to design a low loss hollow core anti-resonant fiber applied in the 1.5~3.0 μm band. The results show that the effect of limiting loss is better when the negative curvature decreases and the positive curvature increases. The lowest confinement loss is 8.22×10-2 dB/km at the wavelength of 2.1 μm when the semi-circular tube is close to the core and the elliptical tube is far away from the core, as well as the circular radius ry=25 μm, the semi-major axis of the ellipse rx=65 μm, the semi-minor axis of the ellipse ry=25 μm..
Journal of Infrared and Millimeter Waves
- Publication Date: Mar. 12, 2020
- Vol. 39, Issue 1, 32 (2020)
The influence of annealing temperature on the structure and optical properties of silicon films deposited by electron beam evaporation
Bao-Jian LIU, Wei-Bo DUAN, Da-Qi LI, De-Ming YU, Gang CHEN, and Ding-Quan LIU
In this paper, the influence of annealing temperature on the structure and optical properties of silicon films was systemically investigated. Silicon films were deposited by electron beam evaporation and then annealed in N2 atmosphere within a temperature range from 200 to 500 °C. The films were characterized by XIn this paper, the influence of annealing temperature on the structure and optical properties of silicon films was systemically investigated. Silicon films were deposited by electron beam evaporation and then annealed in N2 atmosphere within a temperature range from 200 to 500 °C. The films were characterized by X-ray diffraction （XRD）, Raman spectroscopy, electronic-spin resonance （ESR） and optical transmittance measurement, respectively. With annealing temperature increased, the amorphous network order of silicon films was improved on the short and medium range and the defect density decreased remarkably. When sample being annealed at 400°C, the extinction coefficient k decreased from 6.14×10-3 to a minimum value of 1.02×10-3 （at 1000 nm）, which was due to the lowest defect density, about one fifth of the as-deposited sample. The results showed that annealing at an appropriate temperature could effectively reduce the optical absorption of silicon films in the near infrared region, which were very critical for the application in optical thin film coating devices..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 20, 2020
- Vol. 39, Issue 1, 1 (2020)
Feng-Ling WANG, Lei CHEN, Qiu-Bo ZHANG, Li XU, Hui LI, Hai-Zhu WANG, Yong-Qin HAO, and Xiao-Hui MA
A high-refractive-index contrast subwavelength grating （HCG） for 850 nm GaAs-based VCSELs was designed. The whole structure is based on GaAs material system，including a grating layer， a stress buffer layer designed to alleviate its stress problem and an AlOx low refractive index sub-layer oxidized by AlGaAs or AlAs. ThA high-refractive-index contrast subwavelength grating （HCG） for 850 nm GaAs-based VCSELs was designed. The whole structure is based on GaAs material system，including a grating layer， a stress buffer layer designed to alleviate its stress problem and an AlOx low refractive index sub-layer oxidized by AlGaAs or AlAs. The reflection characteristics of the HCG are simulated by Rsoft software， and the effects of different grating parameters on reflection spectrum are analyzed. In particular， the effects of stress buffer layer and low refractive index sub-layer on characteristics of gratings are investigated. The 850 nm TM mode HCG shows a very good reflection characteristic. It has a large reflection bandwidth of up to 91 nm with its reflectivity more than 99.9%， and the ratio with the center wavelength reaches 10.7%. Moreover， its reflectivity for TE mode is ensured to be lower than 90%， showing good polarization selectivity. This HCG can replace P-type distributed Bragg reflectors in VCSEL， providing high reflectivity， wide bandwidth， and good stability..
Journal of Infrared and Millimeter Waves
- Publication Date: Mar. 12, 2020
- Vol. 39, Issue 1, 19 (2020)
Millimeter Wave and Terahertz Technology
Terahertz beam reconfigurable micro-strip Quasi-Yagi-Uda antenna based on monolayer graphene
Wen-Long YAO, Xu-Guang GUO, Yi-Ming ZHU, and Ping LI
We propose a beam reconfigurable micro-strip quasi-Yagi-Uda （QYU） antenna operating at terahertz （THz） frequencies. The antenna, on a metal-backed SiO2 substrate, consists of a metallic micro-strip transmission line, a metallic reflector, a metallic half-round micro patch, and three groups of monolayer-graphene-patch dWe propose a beam reconfigurable micro-strip quasi-Yagi-Uda （QYU） antenna operating at terahertz （THz） frequencies. The antenna, on a metal-backed SiO2 substrate, consists of a metallic micro-strip transmission line, a metallic reflector, a metallic half-round micro patch, and three groups of monolayer-graphene-patch directors. Because the conductivities of the graphene patches can be electrically tuned, the radiation direction of the QYU antenna can be dynamically controlled by adjusting the bias voltages applied to the graphene patches. The basic properties and the tunable behaviors of the antenna are systemically simulated and optimized. It has very fast modulation speed and very low return loss. In particular, the numerical results show that the main radiation lobe angle φ （azimuth angle） of the QYU antenna can be swept from 30° to 150° in θ=60° （zenith angle） plane with different configurations of bias voltages applied to the graphene-patch directors. The proposed antenna is very suitable for THz beam reconfigurable applications, such as phased array radar systems..
Journal of Infrared and Millimeter Waves
- Publication Date: Mar. 12, 2020
- Vol. 39, Issue 1, 39 (2020)
Gui-Yang SU, Cong-Zheng HAN, Yong-Heng BI, Kun LIU, and Lei BAO
The use of microwave links in wireless networks to monitor rainfall and water vapor is the latest technology in atmospheric environmental monitoring. This technology can measure meteorological elements such as rainfall and water vapor near the surface and has the advantages of high spatial and temporal resolution and lThe use of microwave links in wireless networks to monitor rainfall and water vapor is the latest technology in atmospheric environmental monitoring. This technology can measure meteorological elements such as rainfall and water vapor near the surface and has the advantages of high spatial and temporal resolution and low cost. The water vapor density from June 13, 2017 to July 13, 2017 is calculated and analyzed by using the data of the microwave communication link in the E-band of Gothenburg provided by Ericsson, the data of meteorological station 1 provided by the meteorological station at one end of the link and the data of meteorological station 2 provided by the meteorological website of the Swedish Institute of Meteorology and Hydrology （SMHI）. The results show that the environmental conditions at different locations in the same area have certain differences, the temperature of the same area shows a variation ![]()
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Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 20, 2020
- Vol. 39, Issue 1, 47 (2020)
Tong FANG, Li-Yuan LIU, Zhao-Yang LIU, Peng FENG, Yuan-Yuan LI, Jun-Qi LIU, Jian LIU, and Nan-Jian WU
A 3.0 THz detector based on plasma-wave theory proposed by Dyakonov and Shur was designed and fabricated in 65 nm standard CMOS process, the detector consists of a patch antenna, a NMOS field effect transistor, a matching network, and a notch filter. The detector can achieve a room-temperature responsivity （Rv） of 526 A 3.0 THz detector based on plasma-wave theory proposed by Dyakonov and Shur was designed and fabricated in 65 nm standard CMOS process, the detector consists of a patch antenna, a NMOS field effect transistor, a matching network, and a notch filter. The detector can achieve a room-temperature responsivity （Rv） of 526 V/W and a noise equivalent power （NEP） of 73 pW/Hz1/2. The terahertz scanning imaging system was built with the detector and stepper motor, and the far-field shape of the terahertz source beam was obtained, the full width at half maximum （FWHM） of the beam is 240 μm; and the image of the polyformaldehyde toothpick and tree leaf were obtained through the scanning imaging system, it shows that CMOS terahertz detectors have potential applications in the imaging field..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 20, 2020
- Vol. 39, Issue 1, 56 (2020)
Remote Sensing Technology and Application
Peng-Fei TANG, Ze-Lang MIAO, Cong LIN, Pei-Jun DU, and Shan-Chuan GUO
Supervised classification is a vital approach to extract impervious surface areas (ISA) from satellite images, but the training samples need to be provided through heavy manual work. To address it, this study proposed an automatic method to generate training samples from high-resolution night light data, considering thSupervised classification is a vital approach to extract impervious surface areas (ISA) from satellite images, but the training samples need to be provided through heavy manual work. To address it, this study proposed an automatic method to generate training samples from high-resolution night light data, considering that nighttime lights generated by human activities is strongly correlated with impervious surface. First, positive and negative samples for ISA were located according to the distribution of nighttime lights. Second, the feature sets were constructed by calculating the spectral and texture feature from the OLI images. Third, an ensemble ELM classifier was selected for ISA classification and extraction. Four large cities were selected as study areas to examine the performance of the proposed method in different environment. The results show that the proposed method can automatically and accurately acquire ISA with an overall accuracy higher than 93% and Kappa coefficient higher than 0.87. Furthermore, comparative experiments by biophysical composition index (BCI)and classification by manual sample were conducted to evaluate its superiority. The results show that our method has better separability for ISA and soil than the BCI. In general, the proposed method is superior to manual methods, except Harbin mostly because some impervious surfaces with weak light intensity are selected as negative samples..
Journal of Infrared and Millimeter Waves
- Publication Date: Mar. 12, 2020
- Vol. 39, Issue 1, 128 (2020)
Wei LIU, Hai-Xia SUN, and Xiao-Bo YANG
Hierarchical spectrum recognition is pointed out in the aspect of hyper-spectralimage classification using Hyperion imagesof Lanzhou and Yulin in China， by the comparison study of SVM supervised classification.There are 4 problems for hyper-spectralimage classification: spectral information fidelity image fusion， extraHierarchical spectrum recognition is pointed out in the aspect of hyper-spectralimage classification using Hyperion imagesof Lanzhou and Yulin in China， by the comparison study of SVM supervised classification.There are 4 problems for hyper-spectralimage classification: spectral information fidelity image fusion， extraction of sensitive band， removal of "salt and pepper effect" which avoids misclassification for "same body with different spectrum" phenomenon. Hierarchical spectrum recognitionputs forward 4 methods for solving these problems，which are WP-GS image fusion， derivative transformation， object oriented segmentation with 4 scales and multispectral SAM. Hierarchical spectrum recognitioncan identify 9 kinds land type exactly， based on sensitive bands extracted from derivative transformationimage. Visual examination and quantifiable evaluation have been executed to verify authenticity. By contrast， SVM supervised classification is tested， with Gram-Schmidt Spectral sharpening/ Savitzky-Golay convolution filtering/PCA transformation.Using the method of hierarchical spectrum recognition proposed in this paper， the above 4 problems for hyper-spectralimage classification are solved， and good classification results is achieved， with overall classification accuracy and kappa coefficient as 89.52%， 0.852 in Lanzhou， 91.12%、0.873 in Yulin. Growth of 18.68% in Lanzhou and 17.80% in Yulin for overall classification accuracy， as well as17.52% in Lanzhou and 16.89% in Yulin for kappa coefficient are achieved compared with SVM supervised classification.Hierarchical spectrum recognition can provide more accurate recognition results are provided for Hyperion images classification in comparison with SVM supervised classification ..
Journal of Infrared and Millimeter Waves
- Publication Date: Mar. 12, 2020
- Vol. 39, Issue 1, 99 (2020)
Xue-Ling LI, Ying-Ying DONG, Yi-Ning ZHU, and Wen-Jiang HUANG
Regional leaf area index （LAI） mapping is important for crop growth monitoring and yield estimation. Due to the lower accuracy and instability of statistical models for regional LAI estimation, we proposed a new deep neural network model, i.e. Small Simple Learning LAI-Net （SSLLAI-Net）, based on small sample training, Regional leaf area index （LAI） mapping is important for crop growth monitoring and yield estimation. Due to the lower accuracy and instability of statistical models for regional LAI estimation, we proposed a new deep neural network model, i.e. Small Simple Learning LAI-Net （SSLLAI-Net）, based on small sample training, to achieve stable relationship between hyperspectral reflectance and LAI. The new proposed SSLLAI-Net was constructed with two convolution layers, one pooling layer and three connect layers, for which the inputs and outputs were hyperspectral reflectance and LAI estimation. Moreover, SSLLAI-Net could support small training sets. We applied SSLLAI-Net to an Environmental Mapping and Analysis Program （EnMAP） hyperspectral imagery for regional LAI mapping, in which cereals, maize, rape seed and other crops are selected as our objects. The achieved R2 values for estimated LAI of cereals, maize, rape seed and other crops were 0.95, 0.99, 0.98 and 0.90 based on small training sets with 50 samples, while for the inputs with noise, the R2 values were 0.95、0.98、0.96 and 0.89, respectively. In all, our new proposed SSLLAI-Net has high precision of regional LAI mapping, stability and noise resistance with hyperspectral remote sensing observations..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 20, 2020
- Vol. 39, Issue 1, 111 (2020)
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