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Large aperture phase-coded diffractive lens for achromatic and 16°field-of-view imaging with high efficiency

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Chinese Physics B 2022年第7期31卷 349-360页

作者： Gu Ma Peng-Lei Zheng Zheng-Wen Hu Suo-Dong Ma Feng Xu Dong-Lin Pu Qin-Hua Wang School of Optoelectronic Science and Engineering and Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow UniversitySuzhou 215006China Key Laboratory of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Laboratory of Modern Optical Technologies of Education Ministry of China Soochow UniversitySuzhou 215006China CAS Key Laboratory of Space Precision Measurement Technology Xi’an 710119China

Diffractive lenses(DLs)can realize high-resolution imaging with light weight and compact *** DLs suffer large chromatic and off-axis aberrations,which significantly limits their practical *** many achromatic methods have been proposed,most of them are used for designing small aperture DLs,which have low diffraction *** the designing of diffractive achromatic lenses,increasing the aperture and improving the diffraction efficiency have become two of the most important design ***,a novel phase-coded diffractive lens(PCDL)for achromatic imaging with a large aperture and high efficiency is proposed and demonstrated experimentally,and it also possesses wide field-of-view(FOV)imaging at the same *** phase distribution of the conventional phase-type diffractive lens(DL)is coded with a cubic function to expand both the working bandwidth and the FOV of conventional *** proposed phase-type DL is fabricated by using the laser direct writing of grey-scale patterns for a PCDL of a diameter of 10 mm,a focal length of 100 mm,and a cubic phase coding parameter of 30π.Experimental results show that the working bandwidth and the FOV of the PCDL respectively reach 50 nm and 16°with over 8%focusing efficiency,which are in significant contrast to the counterparts of conventional DL and in good agreement with the theoretical *** work provides a novel way for implementing the achromatic,wide FOV,and high-efficiency imaging with large aperture DL.

关键词： achromatic imaging diffractive lens phase coding large aperture high efficiency

A high efficiency PWM CMOS class-D audio power amplifier

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Journal of Semiconductors 2009年第2期30卷 48-53页

作者：朱樟明刘帘曦杨银堂雷晗 Institute of Microelectronics Xidian University Xi'an Power-Rail Micro Co. Ltd

Based on the difference close-loop feedback technique and the difference pre-amp, a high efficiency PWM CMOS class-D audio power amplifier is proposed. A rail-to-rail PWM comparator with window function has been embedded in the class-D audio power amplifier. Design results based on the CSMC 0.5μm CMOS process show that the max efficiency is 90%, the PSRR is -75 dB, the power supply voltage range is 2.5-5.5 V, the THD＋N in 1 kHz input frequency is less than 0.20%, the quiescent current in no load is 2.8 mA, and the shutdown current is 0.5 pA, The active area of the class-D audio power amplifier is about 1.47 × 1.52 mm^2. With the good performance, the class-D audio power amplifier can be applied to several audio power systems.

关键词： class-D audio amplifier PWM CMOS high efficiency rail-to-rail comparator difference

Device simulation of lead-free CH_3NH_3SnI_3 perovskite solar cells with high efficiency

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Chinese Physics B 2016年第10期25卷 554-561页

作者：杜会静王韦超朱键卓 College of Science Yanshan University

The lead-free perovskite solar cells(PSCs) have drawn a great deal of research interest due to the Pb toxicity of the lead halide *** a viable alternative to CHNHPbX,because it has a narrower band gap of 1.3 eV and a wider visible absorption spectrum than the lead halide *** progress of fabricating tin iodide PSCs with good stability has stimulated the studies of these CHNHSnIbased cells *** the paper,we study the influences of various parameters on the solar cell performance through theoretical analysis and device *** is found in the simulation that the solar cell performance can be improved to some extent by adjusting the doping concentration of the perovskite absorption layer and the electron affinity of the buffer and HTM,while the reduction of the defect density of the perovskite absorption layer significantly improves the cell *** further optimizing the parameters of the doping concentration(1.3 × 10cm~3) and the defect density(1 × 10cm~3) of perovskite absorption layer,and the electron affinity of buffer(4.0 eV) and HTM(2.6 eV),we finally obtain some encouraging results of the Jof 31.59 mA/cm~2,Vof 0.92 V,FF of 79.99%,and PCE of 23.36%.The results show that the lead-free CHNHSnIPSC is a potential environmentally friendly solar cell with high *** the Snstability and reducing the defect density of CHNHSnIare key issues for the future research,which can be solved by improving the fabrication and encapsulation process of the cell.

关键词： CH_3NH_3SnI_3 perovskite solar cells device simulation high efficiency

A high efficiency charge pump circuit for low power applications

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Journal of Semiconductors 2010年第1期31卷 88-92页

作者：冯鹏李昀龙吴南健 State Key Laboratory for Super Lattices and Microstructures Institute of SemiconductorsChinese Academy of Sciences

A high efficiency charge pump circuit is designed and realized. The charge transfer switch is biased by the additional capacitor and transistor to eliminate the influence of the threshold voltage. Moreover, the bulk of the switch transistor is dynamically biased so that the threshold voltage gets lower when it is turned on during charge transfer and gets higher when it is turned off. As a result, the efficiency of the charge pump circuit can be improved. A test chip has been implemented in a 0.18μm 3.3 V standard CMOS process. The measured output voltage of the eight-pumpingstage charge pump is 9.8 V with each pumping capacitor of 0.5 pF at an output current of 0.18 μA, when the clock frequency is 780 kHz and the supply voltage is 2 V. The charge pump and the clock driver consume a total current of 2.9 μA from the power supply. This circuit is suitable for low power applications.

关键词： high efficiency low power charge pump circuit high-voltage generator standard CMOS process

Design of high efficiency dual-mode buck DC-DC converter

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Journal of Semiconductors 2010年第11期31卷 88-92页

作者：来新泉曾华丽叶强何惠森张莎莎孙煜晴 Institute of Electronic CAD Xidian University Key Laboratory of high-Speed Circuit Design and EMC Ministry of EducationXidian University

A buck DC-DC switching regulator with high efficiency is implemented by automatically altering the modulation mode according to load current,and it can operate with an input range of 4.5 to 30 *** light load current,the converter operates in skip *** converter enters PWM mode operation with increasing load *** reduces the switching loss at light load and standby state,which results in prolonging battery lifetime and stand-by ***, externally adjustable soft-start minimizes the inrush supply current and avoids the overshoot of output voltage at initial *** regulator is fabricated by a 0.6μm CDMOS *** test results show that,under the condition of 3.3 V output,the efficiency is up to 64%at 5 mA and the maximum efficiency is 95.5%.

关键词： high efficiency soft-start skip mode PWM mode

high efficiency Al-Free 980 nm InGaAs/ InGaAsP/ InGaP Strained Quantum Well Lasers

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Journal of Semiconductors 2000年第5期21卷 417-420页

作者：徐遵图杨国文张敬明马骁宇徐俊英沈光地陈良惠中科院半导体所北京 100083 北京工业大学北京市光电子技术实验室北京 100022

high efficiency Al\|free InGaAs/InGaAsP/InGaP lasers emitting at 980nm are fabricated by MOCVD. The lasers exhibit a high internal quantum efficiency of 95% and a low internal loss of 1\^8 cm\+\{-1\}. Low threshold current density of 190A/cm\+2 and high slope efficiency of 1\^06W/A are obtained by lasers with 800μm cavitylength. A high characteristic temperature 210℃ is also obtained by replacing the GaAs barrier with high\|bandgap InGaAsP barrier. The measured vertical and parallel divergence angle are 40° and 8°, respectively.

关键词： quantum well laser high efficiency Al\|free

A high efficiency and power factor, segmented linear constant current LED driver

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Journal of Semiconductors 2015年第4期36卷 165-171页

作者：励勇远过伟朱樟明 School of Microelectronics Xidian University

A high efficiency, high power factor, and linear constant current LED driver based on adaptive seg- mented linear architecture is presented. When the input voltage varied, the proposed LED driver automatically switched over LED strings according to the segmented LED voltage drop, which increased the LED lighting time. The efficiency and power factor are improved, while the system design is simplified by this control scheme. Without the usage of electrolytic capacitor and magnetic components, the proposed driver possesses advantages of smaller size, longer lifetime and lower cost over others. The proposed driver is implemented in 0.8 μm 5 V/40 V HVCMOS process, which occupies an active area of 820× 920μm2. The measured results show that the average value of the internal reference voltage is 500 4- 7 mV, with a standard deviation of only 4.629 mV, thus LED current can be set accurately. Under 220 V root mean square 50 Hz utility voltage and the number ratio of the three LED strings being 47 ： 17 ： 16, the system can realize a high power factor of 0.974 and power conversion efficiency of 93.4%.

关键词： high efficiency high power factor segmented linear constant LED driver

A 1.8–3 GHz-band high efficiency GaAs pHEMT power amplifier MMIC

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Journal of Semiconductors 2015年第12期36卷 124-127页

作者：戈勤陶洪琪余旭明 Nanjing Electronic Devices Institute

This paper describes an S-band wideband high efficiency power amplifier based on the Nanjing Electron Device Institute＇s Ga As p HEMT monolithic microwave integrated circuit（MMIC） technology. To realize high efficiency, the two stage power amplifier is designed with a driver ratio of 1 ： 8. The low-pass filter/high-pass filter combined matching circuit is applied to the amplifier to reduce the chip size, as well as to realize the optimum impedances over a wide bandwidth for high efficiency at each stage. Biased at class AB under a drain supply voltage of 5 V, the amplifier delivers 33–34 dBm saturated output power across the frequency range of 1.8 to 3GHz with associated power-added efficiency of 35%–45% and very flat power gain of 25–26 dB in CW mode. The size of this MMIC is very compact with 2.72.75 mm^2.

关键词： wideband MMIC GaAs pHEMT power amplifier high efficiency

high efficiency,low threshold,high repetition rate H-βFraunhofer line light at 486.1 nm generation by an intracavity frequency-doubled optical parametric oscillator

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Chinese Optics Letters 2023年第9期21卷 101-106页

作者：李翔翔白云涛丁欣蒋国鑫雷鹏张兴瑞孙杨杜建耕危芳莹张若凡吴亮张贵忠姚建铨 Institute of Laser and Opto-electronics School of Precision Instrument and Opto-electronics EngineeringTianjin UniversityTianjin 300072China Key Laboratory of Opto-electronics Information Technology Ministry of EducationTianjin UniversityTianjin 300072China

A high efficiency,low threshold,high repetition rate H-βFraunhofer line light at 486.1 nm was demonstrated.A high-efficiency KTP optical parametric oscillator was achieved by double-pass pumping with a high-maturity 5 kHz 532 nm *** to the efficient intracavity frequency doubling of the circulating signal wave by a BIBO crystal,the threshold pump power of the 486.1 nm output was 0.9 W,and the maximum output power of 1.6 W was achieved under the pump power of7.5 *** optical–optical conversion efficiency was 21.3%,with the pulse duration of 45.2 ns,linewidth of~0.12 nm,and beam quality factor M~2 of 2.83.

关键词： 486.1 nm H-βFraunhofer line intracavity frequency-doubled optical parametric oscillator high efficiency low threshold high repetition rate