Journals >Journal of Infrared and Millimeter Waves
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2019
Volume: 38 Issue 5
21 Article(s)
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Wet etching for InAs-based InAs/Ga(As)Sb superlattice long wavelength infrared detectors
WU Jia, XU Zhi-Cheng, CHEN Jian-Xin, and HE Li
Wet chemical etching of InAs-based InAs/Ga(As)Sb superlattice long wavelength infrared photodiodes was studied in this paper.The etching experiments using citric acid,orthophosphoric acid and hydrogen peroxidewere carried out on InAs,GaSb bulk materials and InAs/Ga(As)Sb superlattices with different solution ratios. AnWet chemical etching of InAs-based InAs/Ga(As)Sb superlattice long wavelength infrared photodiodes was studied in this paper.The etching experiments using citric acid,orthophosphoric acid and hydrogen peroxidewere carried out on InAs,GaSb bulk materials and InAs/Ga(As)Sb superlattices with different solution ratios. An optimized etching solution for the InAs-based superlattices has been obtained. The etched surface roughness is only 1 nm. InAs-based superlattice LWIR detectors with 50 % cut-off wavelength of 12 μm were fabricated. The photodetectors etched with optimized solution ratio show low surface leakage characteristic.At 81 K temperature, the surface resistivity ρSurface of the detector is 4. 4 × 103 Ωcm..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 549 (2019)
The effect of Mn doping on the interband transition and band tail absorption characteristics of Mn:(Pb, Sr)TiO3 ferroelectric thin films
Mn composition dependence of optical properties,especially interband electronic transition and bandtail absorption behaviors,in Mn doped(Pb,Sr) TiO3(PST)films were investigated by transmittance spectrosco. py. The optical parameters of Mn doped PST films in transparent region were evaluated by Cauchy model. The decreasMn composition dependence of optical properties,especially interband electronic transition and bandtail absorption behaviors,in Mn doped(Pb,Sr) TiO3(PST)films were investigated by transmittance spectrosco. py. The optical parameters of Mn doped PST films in transparent region were evaluated by Cauchy model. The decrease of optical band gap and the expansion of the band tail states with the increasing of Mn dopant amount were observed. The shrinkage of optical band gap is attributed to lowering the bottom of conduction bands by Mn 3d orbitals and the decrease of lattice constant in Mn doped PST films.Meanwhile,the random occupation of Mn ion and the increase of oxygen vacancy after Mn doping are the main causes for the expansion of localized states in band tails..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 554 (2019)
Enhancement of excited-state emission of InAs/GaAs quantum dots with large-period photonic crystal
QIN Lu, XU Bo, and XU Xing-Sheng
In this study,the photoluminescence spectra of InAs/GaAs quantum dots material with photonic crys. tals were investigated by laser diode excitation. The photonic crystals were fabricated in the material of InAs/ GaAs quantum dots by laser holography and wet etching method. It was found that the spectra from quantum dotIn this study,the photoluminescence spectra of InAs/GaAs quantum dots material with photonic crys. tals were investigated by laser diode excitation. The photonic crystals were fabricated in the material of InAs/ GaAs quantum dots by laser holography and wet etching method. It was found that the spectra from quantum dots with photonic crystals appeared multi-peak structure; the enhancement and modification to the short-wavelength component were more pronounced than those to the long-wavelength components. The photoluminescence fromInAs/GaAs quantum dots was modified by photonic crystals,and the emission from excited states was significant. ly enhanced..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 559 (2019)
Numerical study of a tungsten twin-cross-grating-based solar selective absorber
ZHANG Jing-Ru, TU Hua-Tian, ZANG Kai-Yan, HU Er-Tao... and CHEN Liang-Yao|Show fewer author(s)
Based on the six-layered metal/dielectric film structure,a new 2D tungsten twin-cross-grating-based so.lar selective absorber(SSA)has been proposed to improve the optical absorption in the solar radiation region. The weighted average absorptivity before the cut-off wavelength is about 96. 5%,and the calculated emissiviBased on the six-layered metal/dielectric film structure,a new 2D tungsten twin-cross-grating-based so.lar selective absorber(SSA)has been proposed to improve the optical absorption in the solar radiation region. The weighted average absorptivity before the cut-off wavelength is about 96. 5%,and the calculated emissivity at 850 K is about 0. 086. The mechanisms of high absorption in the solar region have been further analyzed by field intensity distribution in the SSA structure. The absorber also has the feature to be less polarization-dependent and broad angular-independent up to 50°,which satisfies the required conditions of the SSA device in applications.Biography: ZHANG Jing-Ru(1994-), female,Shanghai, master. Research area involves optic science and engineering.
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 566 (2019)
Investigation of large power microwave nonlinear effects on amplitude-phase controller chip for Ka-band phased array radar T/R modules
GUO Guo, XU Xiong, WEI Yan-Yu, and GUO Chang-Yong
Large power microwave nonlinear effects on amplitude-phase controller chip were experimentally test. ed and theoretical analyzed. This chip had the typical application on Ka-band phased array radar(PAR)transmit/receive(T/R)modules. The test platform was built up by a solid source and a pulsed magnetron to generate largLarge power microwave nonlinear effects on amplitude-phase controller chip were experimentally test. ed and theoretical analyzed. This chip had the typical application on Ka-band phased array radar(PAR)transmit/receive(T/R)modules. The test platform was built up by a solid source and a pulsed magnetron to generate large power Ka-band microwave. The degradation and destroy phenomenon were observed distinctly as the input power amplitudes were improved. The total-state phase characteristics and the degradation thresholds of the selected chiped are obtained through a series of experimental tests. At last,the results are given by figures and the damage mecha. nism is theoretically analyzed.of China(61571078,61801088,11505043)and the National Key R&D Program of China(2017YFE0300200,2017YFE0300201)..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 572 (2019)
Rotation-invariant infrared aerial target identification based on SRC
JIN Lu, LI Fan-Ming, LIU Shi-Jian, and WANG Xiao
Aircraft identification is implemented on thermal images acquired from ground-to-air infrared cameras.SRC is proved to be an effective image classifier robust to noise,which is quite suitable for thermal image tasks.However,rotation invariance is challenging requirements in this task.To solve this issue,a method is proAircraft identification is implemented on thermal images acquired from ground-to-air infrared cameras.SRC is proved to be an effective image classifier robust to noise,which is quite suitable for thermal image tasks.However,rotation invariance is challenging requirements in this task.To solve this issue,a method is proposedto compute the target main orientation firstly,then rotate the target to a reference direction.Secondly,an over-complete dictionary is learned from histogram of oriented gradient features of these rotated targets.Thirdly,a sparse representation model is introduced and the identification problem is converted to a l1-minimization prob. lem.Finally,different aircraft types are predicted based on an evaluation index,which is called residual error.To validate the aircraft identification method,a recorded infrared aircraft dataset is implemented in an airfield.Experimental results show that the proposed method achieves 98. 3% accuracy,and recovers the identity beyond 80% accuracy even when the test images are corrupted at 50%..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 578 (2019)
HgCdTe avalanche photodiode FPA
LI Hao, LIN Chun, ZHOU Song-Min, GUO Hui-Jun... and HE Li|Show fewer author(s)
HgCdTe APDis one ofthe developingtrends ofthirdgeneration inferredFPAdetectors. In this paper. we report the result on a16×16 arrays ofHgCdTe avalanche photodiode with3.56 μmcut-off wavelength. The operability in gain exceeds 90% and relative gain dispersion is lower than 20%. NEPh is about 60 at 6 V bias with excHgCdTe APDis one ofthe developingtrends ofthirdgeneration inferredFPAdetectors. In this paper. we report the result on a16×16 arrays ofHgCdTe avalanche photodiode with3.56 μmcut-off wavelength. The operability in gain exceeds 90% and relative gain dispersion is lower than 20%. NEPh is about 60 at 6 V bias with excess noise factor closeto 1.2..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 587 (2019)
The influence of sulfide passivation on optical properties of InAs nanowires
LI Bao-Bao, LI Sheng-Juan, CHEN Gang, LI Shi-Min, and WANG Xing-Jun
To solve the problem oflow luminescence efficiency causedby the surface oxidation ofInAs nanowires,C18H38S and(NH4)2S were adopted to passivate zinc blende(ZB)InAs nanowires synthe-sizedby chemical vapor deposition(CVD). Photoluminescence(PL)spectra of(before and after sul-fide passivation)InAs nanowires were performedTo solve the problem oflow luminescence efficiency causedby the surface oxidation ofInAs nanowires,C18H38S and(NH4)2S were adopted to passivate zinc blende(ZB)InAs nanowires synthe-sizedby chemical vapor deposition(CVD). Photoluminescence(PL)spectra of(before and after sul-fide passivation)InAs nanowires were performed. The experimental results show that the PLemission efficiency of C18H38S and(NH4)2S passivated InAs nanowires are ~ 6 times and ~ 7 times higher than that of unpassivatedInAs nanowires at 25K,respectively. In addition,the PL of (NH4)2S passivation InAs nanowires is detected at room temperature, which provides a possibility for future InAs nanow-iresbasedmiddleinfrarednanophotondevices..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 591 (2019)
Optimization of InAlAsSb SACM APD with a heterojunction multiplication layer
JIANG Yi, and CHEN Jun
For avalanche photodiodes(APDs), low operation voltage is required for integrated circuit stability and low power consumption. In this paper,a model for InAlAsSb separate absorption, charge,andmultiplication(SACM)APDisestablished. Togethighergainatlowerreversedbiasvolt-age without sacrificing the operating voltage rangFor avalanche photodiodes(APDs), low operation voltage is required for integrated circuit stability and low power consumption. In this paper,a model for InAlAsSb separate absorption, charge,andmultiplication(SACM)APDisestablished. Togethighergainatlowerreversedbiasvolt-age without sacrificing the operating voltage range,a high/low band gap multiplication layer is adopt-ed. Theeffectsofthethicknessanddopingconcentration ofthemultiplicationlayeronthe dark-current and the break-down voltage have been investigated. By optimization of the doping concentration,the break-down voltage and punch-through voltage can be decreased simultaneously..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 598 (2019)
Design of three-dimensional millimeter wave radar for collision avoidance
TANG Yao, LI Bo, YAN Zhong-Jiang, YANG Mao, and DU Zi-Cheng
Limited by the flexibility of beam scheduling and receiving channel number,the range/azi-muthtwo-dimensional(2D)scan is mainlyusedinthe currentdiversityphasedarrayradarfor collision avoidance. Duetothelack oftargets'heightinformation,ifthere isahigh/low targetin frontofthe ra-dar which does not affect the passage oLimited by the flexibility of beam scheduling and receiving channel number,the range/azi-muthtwo-dimensional(2D)scan is mainlyusedinthe currentdiversityphasedarrayradarfor collision avoidance. Duetothelack oftargets'heightinformation,ifthere isahigh/low targetin frontofthe ra-dar which does not affect the passage of the carrier,it will likely to cause false alarm. Aiming at this problem,this paper proposes an antenna layout and signal processing method based on the combina-tion of MIMO and diversity phased array radar to realize the three-dimensional detection. Compared with the two-dimensional collision avoidance radar,this method can effectively realize 3D detection without increasing the number of radar receiving channels and the radar size. Compared with the 2D sparse array radar,the radar designed in this paper does not generate azimuth grating lobe,which is suitable for multi-target detection under complex background..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 604 (2019)
Beam-wave interaction analysis of a megawatt coaxial cavity gyrotron for controlled thermonuclear fusion
ZHANG Shan, XUE Qian-Zhong, LIU Gao-Feng, WANG Xue-Wei... and ZHANG Lian-Zheng|Show fewer author(s)
Relative to the single-cavitygyrotrons operatingin high-order mode,the coaxial cavitygyro-trons have the advantages of reducing mode competition,improvingthe stability of single mode opera-tion and increasing the power capacity. Therefore,the coaxial cavity gyrotrons are more suitable for electron cyclotron resonance hRelative to the single-cavitygyrotrons operatingin high-order mode,the coaxial cavitygyro-trons have the advantages of reducing mode competition,improvingthe stability of single mode opera-tion and increasing the power capacity. Therefore,the coaxial cavity gyrotrons are more suitable for electron cyclotron resonance heating and electron cyclotron current drivingin controlled thermonuclear fusion and attract much attention. The effects of structure parameters,electron beam parameters and ohmic losses on the beam-wave interaction of a coaxial cavity gyrotron operating at 170 GHz, TE34,11 mode were investigated in detail. Firstly,the mode selection of 170-GHz MW-class gyrotrons wasanalyzed and mode TE34,11 was chosen asthe operating mode. Secondly,based on the time-depen-dent self-consistent nonlinear theory,a time-domain single-mode steady-state code was written to studythe beam-wave interaction. Theinfluencesofthebeam current,the magneticfield andtheohmic losses on the cavity walls were analyzed and the operatingparameters were optimized. The simulation results show that when the voltage,the beam current and the axialguiding magnetic field are designed to be 65 kV,68A and 6.58 T,an output with 2.18 MW power and 49.23 % efficiency can be ob-tained, the peak ohmic loss density on the outer wall of the cavity is 1.94kW/cm2, and the peak ohmic loss density on the insertis less than 0.15W/cm2. The interaction efficiency decreases with the in-crease of electron velocity spread, and the output frequency shifts downward. The thickness of electron beam has similar effects on the interaction..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 613 (2019)
Calibration and measurement of internal stray radiation in thermal infrared spectrometer system
PENG Jun, HE Qi, ZHANG Ying, WANG Bai-Hai... and LIU Yin-Nian|Show fewer author(s)
Amethod for measuring internal stray radiation in thermal infrared spectrometer system was proposed in this paper,which is based on radiometric calibration of a detector and a thermal infrared spectrometer. The output response curves of detector and the spectrometer system to blackbody radia-tion energy of asingle specAmethod for measuring internal stray radiation in thermal infrared spectrometer system was proposed in this paper,which is based on radiometric calibration of a detector and a thermal infrared spectrometer. The output response curves of detector and the spectrometer system to blackbody radia-tion energy of asingle spectral channelare calibrated separately. Therefore,the internalstray radiation grayvalueandradiation fluxvalueofthespectrometer can be obtained andthegrayvalueand radiation flux of the internal stray radiation at different integration times and temperatures in the system can also be calculated. The proposed method was used to measure the internal stray radiation of an existing spectrometer,and comparative experiments were carried out. Results show that the error between the experimental results and the theoretical predicted values is less than 1%. The proposed method has high maneuverability and can be used to measure the proportion of internal stray radiation in total out-put DN value of the system,predict the influence of refrigeration on internal stray radiation of spec-trometer, and measure the inhibition effect of other internal stray radiation suppression methods..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 621 (2019)
Static and dynamic rubbing positions identification of Cryocooler based on wavelet packet analysis and support vector machine
GAO Sheng, WU Yi-Nong, and JIANG Zhen-Hua
Cryocoolerplaysanextremelyimportantrolein thefield ofinfraredremote sensing. Thenor-maloperationandperformanceofthedetectorwillbeaffectedifthecryocoolerbreaksdown. Anewin-telligent fault diagnosis method for cryocooler has been proposed based on wavelet packet transform, genetic algorithm and SVM for rubbing fault. FirCryocoolerplaysanextremelyimportantrolein thefield ofinfraredremote sensing. Thenor-maloperationandperformanceofthedetectorwillbeaffectedifthecryocoolerbreaksdown. Anewin-telligent fault diagnosis method for cryocooler has been proposed based on wavelet packet transform, genetic algorithm and SVM for rubbing fault. First,wavelet transform is applied to the vibration sig-nal,and the vibration signal is extracted in time domain. The evaluation factors of the combined fea-ture set are calculatedby using the distance evaluation technique,and the corresponding sensitive fea-tures are selected. Then,the parameters of SVM are optimized by genetic algorithm. Finally,the se-lected sensitive features are inputinto the optimizedSVM to identifydifferent machine operation states automatically. The effectiveness of the method is verified by the fault simulation test of the cryocooler. Experimental results show that this method can identify and locate the cryocooler rubbing fault accu-rately,andtheaccuracyis95%..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 627 (2019)
Infrared small target detection based onweighted scene prior
PAN Sheng-Da, ZHANG Su, ZHAO Ming, and AN Bo-Wen
To further to improve the detection accuracy and real-time performance of infrared small tar-get detection at sea,a new method based on weighted scene priors is introduced. Firstly,using the sparse characteristics of the target and the non-local self-correlation characteristics of the sea back-ground,the target-backgroTo further to improve the detection accuracy and real-time performance of infrared small tar-get detection at sea,a new method based on weighted scene priors is introduced. Firstly,using the sparse characteristics of the target and the non-local self-correlation characteristics of the sea back-ground,the target-background separation problem is modeled as a robust low-rank matrix recovery problem. Moreover,the prior information on sea backgroundis addedinto the modelby weighted nu-clear norm to accelerate the decomposition of target and background images’matrix in the algorithm. Finally,the alternatingdirection method of multipliers (ADMM) is introduced to further to accelerate the iteration speed of the solution. The experimental results show that the proposed algorithm can effectively improve the accuracy of target detection. The real-time performance of the algorithm is improvedby 120% compared with the original algorithm..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 633 (2019)
A performance characterization and matching design method of space-based optical detection for weak aerial target
QIAO Kai, ZHI Xi-Yang, YANG Dong, GONG Jin-Nan, and HU Jian-Ming
Aiming for long-distance optical detection of weak aerial targets,we in this paper propose a method of performance characterization and key indexes matching design for a space-based detection system. Firstly,we analyze the main factors that affect the optical detectability of weak targets under complex environment baseAiming for long-distance optical detection of weak aerial targets,we in this paper propose a method of performance characterization and key indexes matching design for a space-based detection system. Firstly,we analyze the main factors that affect the optical detectability of weak targets under complex environment based on the fulllink of the space-based detection system,including scene clut-ter,spectral radiation scale and geometric scale of detection system,etc. We then combine the above influencing factors to establish a performance characterization model which represents the relationship between the image signal-to-noise ratio of target and the above-mentioned influencing factors,that is, the performance representation model ofthe detection system. Finally,taking atypicaldetection scene as an example,by studying signal-to-noise ratio of target under different scene clutter and multi-scale coupling characteristics,the optimization of detection spectrum and its matching design with spatial resolution are proposed,which can provide theoretical basis and scientific guidance for the design of the space-based detection system,demonstration of system indexes and optimization of information processing algorithms..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 642 (2019)
Post-launch calibration and validation of the Geostationary Interferometric Infrared Sounder(GIIRS)on FY-4A
FENG Xuan, LI Li-Bing, CHEN Bo-Yang, ZOU Yao-Pu, and HAN Chang-Pei
The Geostationary Interferometric Infrared Sounder(GIIRS)on board FY-4A is an infrared Fourier transform spectrometer. The primary use ofGIIRSis to support numerical weather predictions byprovidingimprovedtemperature and watervaporprofileinformation,whichrequires high radiomet-ric precision and accuracy. To meet the reThe Geostationary Interferometric Infrared Sounder(GIIRS)on board FY-4A is an infrared Fourier transform spectrometer. The primary use ofGIIRSis to support numerical weather predictions byprovidingimprovedtemperature and watervaporprofileinformation,whichrequires high radiomet-ric precision and accuracy. To meet the requirement,post-launch GIIRS calibration and validation ac-tivities were carried out. The spectral calibration has been done throughdeterminingthe effective sam-pling frequency which is to take advantage of gaseous line center positions known to high accuracy. The radiometric calibration has been performed through using observation of hot and cold black body reference sources as the basis for two-point calibrations at each wavenumber. The amplitude of some spectrum bands was reduced,which maybe causedby some materials gradually releasing alittle gas. The estimated absolute spectral calibration uncertaintyis 10ppm,and the mean brightness temperature differences between GIIRS observations and IASI observations are all less than 1 K in the long-wave andmid-waveband..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 648 (2019)
Research on optical controlled terahertz modulator based on monolayer tungsten disulfide
FU Ya-Zhou, TAN Zhi-Yong, WANG Chang, and CAO Jun-Cheng
Controlling the propagation of terahertz(THz)wave is very important in the application of THz technology. THz modulator is considered to be the key device in next-generation THz wireless communication. A new-type opticallypumpedTHz modulator based on Si-grown monolayer tungsten disulfide(WS2)was demonstrated. WS2acts aControlling the propagation of terahertz(THz)wave is very important in the application of THz technology. THz modulator is considered to be the key device in next-generation THz wireless communication. A new-type opticallypumpedTHz modulator based on Si-grown monolayer tungsten disulfide(WS2)was demonstrated. WS2acts as acatalystdue to the formation ofheterojunction at the junction between Si substrate and WS2,since more carriers are catalyzed at the heterojunction under pumping power,the modulator can achieve more deep modulation depth. The result shows that the modulation depth of this Si-grown monolayerWS2modulator can reach63.6% under the low pumping power of117 mW andthe wavelength ofthe pumplightis 660 nm. This noveltwo-dimensionaltransi-tion metal dichalcogenides with high modulation efficiency have a great prospect in the application of THz technology.动计划(17ZR1448300).
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 655 (2019)
Multimode time domain analysis of terahertz second harmonic cyclotron oscillator
WANG Xue-Wei, XUE Qian-Zhong, ZHANG Shan, ZHAO Guo-Hui, and LIU Gao-Feng
This paper derived time domain multimode formula and combined it with the frequency single modetheoryto investigate mode oscillation and mode interaction of a 394 GHz gyrotron. The gyrotron reaches a TE2261+ and TE2261- modes oscillate at 393.87 GHz in time domain theory while TE2261- cannot oscillate in frequency domaThis paper derived time domain multimode formula and combined it with the frequency single modetheoryto investigate mode oscillation and mode interaction of a 394 GHz gyrotron. The gyrotron reaches a TE2261+ and TE2261- modes oscillate at 393.87 GHz in time domain theory while TE2261- cannot oscillate in frequency domain theory when the beam voltage is 15 kV, the magnetic field is 7.185 T, and beam current is 0.25 A. TE2261+ mode dominates the final oscillation, which output power and efficiency are 136.8 W and 3.6%, respectively. The output characteristics of the operating mode obtained by two theories are identical..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 662 (2019)
910 nm high peak power vertical-cavity surface-emitting laser source
LIANG Xue-Mei, ZHANG Xing, ZHANG Jian-Wei, ZHOU Yin-Li... and WANG Li-Jun|Show fewer author(s)
This paper presents the design method and test results of a 910 nm high peak power vertical-cavity surface-emitting laser(VCSEL)array. More than 2W output power was achievedfor 910 nm VCSEL array under the Quasi-CWdriving current. Under the electric pulseddriving condition with a repetition frequency of 10k Hz and a puThis paper presents the design method and test results of a 910 nm high peak power vertical-cavity surface-emitting laser(VCSEL)array. More than 2W output power was achievedfor 910 nm VCSEL array under the Quasi-CWdriving current. Under the electric pulseddriving condition with a repetition frequency of 10k Hz and a pulse width of 30 ns, the peak output power of a single VCSEL array reached 25.5 W at 60A operating current. With the increase of operating current,the laser spec-trum outputted by VCSEL array shows obvious broadening phenomenon,which proves that the large current drive ofVCSEL array will still produce serious internal thermal effect even at the operation of narrow pulse. When the driving current increases to 60A,the pulse width ofthe laser pulse waveform of VCSEL array only widens by about 6 ns. This proves that VCSEL array has A very superior impulse response characteristic. After beam collimation ofVCSELarray,nearly circular uniform spot was ob-tained atadistance of1 m. We believe that this kind of high power 910 nm array light source has great application potential in the future intelligent driving fields such as vehicle light detection and ranging (LiDAR)..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 668 (2019)
Research on the passive detection technology using space-borne synthesis aperture microwave radiometers for the sea surface target
LU Hai-Liang, LI Yi-Nan, SONG Guang-Nan, LI Shu-Jing... and YANG Dong|Show fewer author(s)
To detect the large-scale vessel targets in the whole day,all-weather and concealed,the syn-thesis aperture microwave radiometers with high resolution are proposed for the first time as a space-borne microwave thermal radiation passive detection system,whichis used to detect the vessel targets on the sea. A novel methoTo detect the large-scale vessel targets in the whole day,all-weather and concealed,the syn-thesis aperture microwave radiometers with high resolution are proposed for the first time as a space-borne microwave thermal radiation passive detection system,whichis used to detect the vessel targets on the sea. A novel methodis proposedto quantitatively evaluate the detection capability of aspace-borne microwave passive detection system. The relationship between system’s main specifications, the microwave radiation cross section ofthe target and the detection distance is established. The detec-tion probability and the detection distance are derived,respectively. Simulation analysis and air-borne experiments are also carried out.Both simulation and experimental results demonstrate the feasibility of the space-borne synthesis aperture microwave thermal radiation passive detection technology with high resolution to detect the large-scale vessel targets. The synthesis aperture microwave radiometers with high resolution can be used as an important complementary system for space-based warning..
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 674 (2019)
[in Chinese]
Journal of Infrared and Millimeter Waves
- Publication Date: Nov. 19, 2019
- Vol. 38, Issue 5, 1 (2019)
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