We experimentally demonstrate a high-speed phosphorescent white light emitting diode （LED） visible light communication （VLC） system without utilizing an optical blue filter. Here, the white light response is equal...We experimentally demonstrate a high-speed phosphorescent white light emitting diode （LED） visible light communication （VLC） system without utilizing an optical blue filter. Here, the white light response is equalized by using the proposed analog equalizers. The 3 dB bandwidth of the VLC link could be extended from 3 to 132 MHz, which allows 330 Mbit/s non-return-to-zero on-off keying （NRZ-OOK） data transmission with a bit error ratio （BER） of 7,2 × 10^-10 and 672 Mbit/s 64-quadrature amplitude modulation （64-QAM） data transmission with a BER of 3.2 × 10^-3. These resultant BERs are less than the forward error correction （FEC） limit of 3.8× 10^-3. The VLC link distance is 1 m using a single 1 W LED. The transmitter and receiver modules are integrated to a compact size. Furthermore, the relationships between the signal performance and illumination level or optical power are investigated and analyzed.展开更多
Since the invention of lasers,spatial-light-modulated laser processing has become a powerful tool for various applications.It enables multidimensional and dynamic modulation of the laser beam,which significantly impro...Since the invention of lasers,spatial-light-modulated laser processing has become a powerful tool for various applications.It enables multidimensional and dynamic modulation of the laser beam,which significantly improves the processing efficiency,accuracy,and flexibility,and presents wider prospects over traditional mechanical technologies for machining three-dimensional,hard,brittle,or transparent materials.In this review,we introduce:(1)The role of spatial light modulation technology in the development of femtosecond laser manufacturing;(2)the structured light generated by spatial light modulation and its generation methods;and(3)representative applications of spatial-light-modulated femtosecond laser manufacturing,including aberration correction,parallel processing,focal field engineering,and polarization control.Finally,we summarize the present challenges in the field and possible future research.展开更多
Obtaining timely and accurate data on the spatiotemporal dynamics of electric power consumption(EPC)is crucial for the effective utilization of electric power in China.The Defense Meteorological Satellite Program’s O...Obtaining timely and accurate data on the spatiotemporal dynamics of electric power consumption(EPC)is crucial for the effective utilization of electric power in China.The Defense Meteorological Satellite Program’s Operational Linescan System(DMSP/OLS)nighttime stable light(NSL)data have good potential for estimating EPC effectively at large scales.However,saturated lighted pixels contained within the NSL data limit the accuracy of EPC estimation.We developed a new method to correct the saturated lighted pixels,using the SPOT VEGETATION(SPOT/VGT)10-day synthesis product(S10)normalized differ-ence vegetation index(NDVI)data and then modeled the spatiotemporal dynamics of EPC in China' Mainland from 2000 to 2008.The results demon-strated the reliability of our approach with an average Rvalue of 0.93(P<0.001)and an average relative error of-28.92%.EPC in China' Mainland showed an average annual growth rate of 13.46% during the study period from 1198.23 billion kWh in 2000 to 3290.51 billion kWh in 2008.EPC in China' Mainland also showed clear regional variation.Northern coastal China and eastern coastal China consumed 37.61%of the total EPC in China' Mainland,with only 25.96% of the population and 6.11% of the area.展开更多
An optically addressed liquid crystal modulator for wavefront control of 1053 nm laser beam is reported in this paper.Its working principle, control method and spatial phase modulation capability are mainly introduced...An optically addressed liquid crystal modulator for wavefront control of 1053 nm laser beam is reported in this paper.Its working principle, control method and spatial phase modulation capability are mainly introduced. A new method of measuring the relationship between gray level and phase retardation is proposed. The rationality of the curve is further confirmed by designing special experiments. According to the curve, several spatial phase distributions have been realized by this home-made device. The results show that, not only the maximum phase retardation is larger than2π for 1053 nm wavelength, but also the control accuracy is high. Compared with the liquid crystal on silicon type spatial light modulator, this kind of modulator has the advantages of generating smooth phase distribution and avoiding the black-matrix effect.展开更多
A 100-J-level Nd:glass laser system in nanosecond-scale pulse width has been constructed to perform as a standard source of high-fluence-laser science experiments. The laser system, operating with typical pulse durati...A 100-J-level Nd:glass laser system in nanosecond-scale pulse width has been constructed to perform as a standard source of high-fluence-laser science experiments. The laser system, operating with typical pulse durations of 3–5 ns and beam diameter 60 mm, employs a sequence of successive rod amplifiers to achieve 100-J-level energy at 1053 nm at3 ns. The frequency conversion can provide energy of 50-J level at 351 nm. In addition to the high stability of the energy output, the most valuable of the laser system is the high spatiotemporal beam quality of the output, which contains the uniform square pulse waveform, the uniform flat-top spatial fluence distribution and the uniform flat-top wavefront.展开更多
基金supported by the National 973Program of China(No.2013CB329205)the National 863Program of China(Nos.2013AA013602,2013AA013603,2013AA03A104,and 2013AA031903)+1 种基金the National Natural Science Foundation of China(Nos.61036002 and61178051)the Beijing Municipal Science and Technology Project(No.Z141100001414004)
文摘We experimentally demonstrate a high-speed phosphorescent white light emitting diode （LED） visible light communication （VLC） system without utilizing an optical blue filter. Here, the white light response is equalized by using the proposed analog equalizers. The 3 dB bandwidth of the VLC link could be extended from 3 to 132 MHz, which allows 330 Mbit/s non-return-to-zero on-off keying （NRZ-OOK） data transmission with a bit error ratio （BER） of 7,2 × 10^-10 and 672 Mbit/s 64-quadrature amplitude modulation （64-QAM） data transmission with a BER of 3.2 × 10^-3. These resultant BERs are less than the forward error correction （FEC） limit of 3.8× 10^-3. The VLC link distance is 1 m using a single 1 W LED. The transmitter and receiver modules are integrated to a compact size. Furthermore, the relationships between the signal performance and illumination level or optical power are investigated and analyzed.
基金This work was supported by the National Key R&D Program of China(Grant No.2021YFB2802000)the National Natural Science Foundation of China(Grant Nos.61827826,62175086,62131018)+1 种基金the Natural Science Foundation of Jilin Province(Grant No.20220101107JC)the Education Department of Jilin Province(Grant No.JJKH20221003KJ).
文摘Since the invention of lasers,spatial-light-modulated laser processing has become a powerful tool for various applications.It enables multidimensional and dynamic modulation of the laser beam,which significantly improves the processing efficiency,accuracy,and flexibility,and presents wider prospects over traditional mechanical technologies for machining three-dimensional,hard,brittle,or transparent materials.In this review,we introduce:(1)The role of spatial light modulation technology in the development of femtosecond laser manufacturing;(2)the structured light generated by spatial light modulation and its generation methods;and(3)representative applications of spatial-light-modulated femtosecond laser manufacturing,including aberration correction,parallel processing,focal field engineering,and polarization control.Finally,we summarize the present challenges in the field and possible future research.
文摘Obtaining timely and accurate data on the spatiotemporal dynamics of electric power consumption(EPC)is crucial for the effective utilization of electric power in China.The Defense Meteorological Satellite Program’s Operational Linescan System(DMSP/OLS)nighttime stable light(NSL)data have good potential for estimating EPC effectively at large scales.However,saturated lighted pixels contained within the NSL data limit the accuracy of EPC estimation.We developed a new method to correct the saturated lighted pixels,using the SPOT VEGETATION(SPOT/VGT)10-day synthesis product(S10)normalized differ-ence vegetation index(NDVI)data and then modeled the spatiotemporal dynamics of EPC in China' Mainland from 2000 to 2008.The results demon-strated the reliability of our approach with an average Rvalue of 0.93(P<0.001)and an average relative error of-28.92%.EPC in China' Mainland showed an average annual growth rate of 13.46% during the study period from 1198.23 billion kWh in 2000 to 3290.51 billion kWh in 2008.EPC in China' Mainland also showed clear regional variation.Northern coastal China and eastern coastal China consumed 37.61%of the total EPC in China' Mainland,with only 25.96% of the population and 6.11% of the area.
文摘An optically addressed liquid crystal modulator for wavefront control of 1053 nm laser beam is reported in this paper.Its working principle, control method and spatial phase modulation capability are mainly introduced. A new method of measuring the relationship between gray level and phase retardation is proposed. The rationality of the curve is further confirmed by designing special experiments. According to the curve, several spatial phase distributions have been realized by this home-made device. The results show that, not only the maximum phase retardation is larger than2π for 1053 nm wavelength, but also the control accuracy is high. Compared with the liquid crystal on silicon type spatial light modulator, this kind of modulator has the advantages of generating smooth phase distribution and avoiding the black-matrix effect.
基金supported by the project of the National Natural Science Foundation of China (grant numbers 61378007 and 61138005)
文摘A 100-J-level Nd:glass laser system in nanosecond-scale pulse width has been constructed to perform as a standard source of high-fluence-laser science experiments. The laser system, operating with typical pulse durations of 3–5 ns and beam diameter 60 mm, employs a sequence of successive rod amplifiers to achieve 100-J-level energy at 1053 nm at3 ns. The frequency conversion can provide energy of 50-J level at 351 nm. In addition to the high stability of the energy output, the most valuable of the laser system is the high spatiotemporal beam quality of the output, which contains the uniform square pulse waveform, the uniform flat-top spatial fluence distribution and the uniform flat-top wavefront.
