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High Power Laser Science and Engineering 2024年第1期12卷 84-98页

作者： Yujia Zhang Wei Fan Jiangfeng Wang Xiaochao Wang Xinghua Lu Dajie Huang Shouying Xu Yanli Zhang Mingying Sun Zhaoyang Jiao Shenlei Zhou Xiuqing Jiang Key Laboratory of High Power Laser and Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghaiChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina

Frequency modulation(FM)-to-amplitude modulation(AM) conversion is an important factor that affects the time±power curve of inertial confinement fusion(ICF) high-power laser facilities. This conversion can impact uniform compression and increase the risk of damage to optics. However, the dispersive grating used in the smoothing by spectral dispersion technology will introduce a temporal delay and can spatially smooth the target. The combined effect of the dispersive grating and the focusing lens is equivalent to a Gaussian low-pass filter, which is equivalent to 8 GHz bandwidth and can reduce the intensity modulation on the target to below 5% with 0.3 nm @ 3 GHz + 20 GHz spectrum phase modulation. The results play an important role in the testing and evaluating of the FM-to-AM on the final optics and the target, which is beneficial for comprehensively evaluating the load capacity of the facility and isentropic compression experiment for ICF.

关键词： dispersion grating frequency modulation-to-amplitude modulation conversion high-power laser facility inertial confinement fusion phase modulation

phase modulation of bcc-structured Fe35Mn25Al15Cr10Ni15 high-entropy alloy by interstitial carbon

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Journal of Iron and Steel Research(International) 2018年第8期25卷 877-882页

作者： Cong-hui Hu Jian-lei Zhang Yun-hu Zhang Ke Han Chun-ming Li Chang-jiang Song Qi-jie Zhai State Key Laboratory of Advanced Special Steel Shanghai Key Laboratory of Advanced Ferrometallurgy and School of Materials Science and Engineering Shanghai University Shanghai 200444 China National High Magnetic Field Laboratory Florida State University Tallahassee FL 32310 USA

High-entropy alloys （HEAs） usually contain more than five alloying elements. The ductility of a body-centered cubic （bcc）- type HEA typically is lower than that of their face-centered cubic （fcc） counterpart. And low ductility restricts engineering applications of the bcc-structured HEAs. In engineering materials, improvement in ductility usually results in deduction of mechanical strength. A method to improve both mechanical strength and ductility in a bcc-structured HEA was proposed by adding interstitial carbon. Experimental results showed that replacement of 5 at.% Cr with 5 at.% C in a bcc-structured Fe35Mn25Al15Cr10Ni15 HEA resulted in an increase in fcc phase from 0.3 to 93.7 vol.%. Strength and ductility increased at the same time. The transition of bcc-structure to fcc-structure along with a remaining small amount of bcc phase improved mechanical properties. This work indicates that interstitial carbon can be employed to modulate the fraction of constituent phases in a bcc-structured HEA to enhance engineering mechanical properties.

关键词： High-entropy alloy Interstitial carbon Constituent phase phase modulation Mechanical property

phase modulation pseudocolor encoding ghost imaging

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Chinese Physics B 2015年第2期24卷 142-145页

作者：段德洋张路杜少将夏云杰 Shandong Provincial Key Laboratory of Laser Polarization and Information Technology Research Institute of LaserQufu Normal University School of Physical Engineering Qufu Normal University School of Physics and Information Technology Jining University

We present a ghost imaging scheme that can obtain a good pseudocolor image of black-and-white objects.The essential idea is to use a multi-wavelength thermal light source and the phase modulation pseudocolor encoding technique,which overcomes the disadvantages of other methods involved spatial filtering.Therefore,the pseudocolor ghost image achieved by this imaging scheme is better than that obtained by other methods in terms of brightness,color,and signal-tonoise ratio.

关键词： ghost imaging pseudocolor phase modulation

Experimental implementation of phase triplicator gratings in a spatial light modulator

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Chinese Optics Letters 2024年第2期22卷 64-69页

作者：高尚 María del Mar Sánchez-López Ignacio Moreno Instituto de Bioingeniería Universidad Miguel HernándezElche 03202Spain Departamento de Física Aplicada Universidad Miguel HernándezElche 03202Spain Departamento de Ciencia de Materiales Óptica y Tec.Electr´onicaUniversidad Miguel HernándezElche 03202Spain

In this work,we compare different methods for implementing a triplicator,a phase grating that generates three equiintense diffraction orders.The design with optimal efficiency features a continuous phase profile,which cannot be easily reproduced,and is typically affected by quantization.We compare its performance with binary and sinusoidal phase profiles.We also analyze the effect of quantizing the phase levels.Finally,a random approach is adopted to eliminate the additional harmonic orders.In all cases,a liquid-crystal-on-silicon spatial light modulator is employed to experimentally verify and compare the different approaches.

关键词： diffraction gratings phase modulation triplicator spatial light modulators

Effective improvement of beam lifetime based on radiofrequency phase modulation at the HLS-II storage ring

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Nuclear Science and Techniques 2021年第1期32卷 1-9页

作者： Yun-Kun Zhao Bao-Gen Sun Ji-Gang Wang Fang-Fang Wu Ping Lu Tian-Yu Zhou San-Shuang Jin National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China

A radiofrequency(RF)phase modulation method is applied to the Hefei Light Source II storage ring to deeply investigate its longitudinal beam characteristics and improve the beam lifetime.A theoretical analytical model and corresponding experimental measurements of single bunch length and island phenomena are examined.From a series of online machine experiments,we demonstrate that the suitable phase modulation amplitude is 0.02 rad,corresponding to an optimum modulation frequency ranging from 19.6 to 20.7 kHz of the RF system.Furthermore,the overall beam lifetime can be increased by a factor of 2.38 as a result of the beam dilution effect.

关键词： phase modulation Amplitude Beam lifetime Longitudinal beam characteristics Beam dilution Island

Research on stimulated Brillouin scattering suppression based on multi-frequency phase modulation

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Chinese Optics Letters 2009年第1期7卷 29-31页

作者：刘英繁吕志伟董永康李强 Institute of Opto-Electronics Harbin Institute of Technology

The method of generating equal-amplitude spectral lines by multi-frequency phase modulation is used in stimulated Brillouin scattering （SBS） suppression. The spectra of three, five, seven, and eleven equalamplitude spectral lines are obtained in experiment with flatnesses less than 0.3 dB. Theoretical research on SBS suppression shows that the threshold power after modulation is in reverse proportion to the maximum square of amplitude moduli of fundamental frequency and the nth harmonic wave. The threshold powers of three, five, seven, and eleven equal-amplitude spectral lines are improved by 5.21, 8.36, 9.39, and 10.76 dB, respectively.

关键词： Brillouin scattering Frequency domain analysis Light polarization phase modulation Polarization Spectrum analysis Stimulated Brillouin scattering Ultrasonics

Effects of group-velocity mismatch and cubic-quintic nonlinearity on cross-phase modulation instability in optical fibers

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Chinese Optics Letters 2007年第9期5卷 534-537页

作者：钟先琼向安平 Department of Optoelectronics and Technology Chengdu University of Information Technology

The synthetic effects of group-velocity mismatch and cubic-quintic nonlinearity on cross-phase modulation induced modulation instability in loss single-mode optical fibers have been numerically investigated. The results show that the quintic nonlinearity plays a role similar to the case of neglecting the group-velocity mismatch in modifying the modulation instability, namely, the positive and negative quintic nonlinearities can still enhance and weaken the modulation instability, respectively. The group-velocity mismatch can considerably change the gain spectrum of modulation instability in terms of its shape, peak value, and position. In the normal dispersion regime, with the increase of the group-velocity mismatch parameter, the gain spectrum widens and then narrows, shifts to higher frequencies, and the peak value gets higher before approaching a saturable value. In the abnormal dispersion regime, two separated spectra may occur when the group-velocity mismatch is taken into account. With the increase of the group-velocity mismatch parameter, the peak value of the gain spectrum gets higher and shorter before tending to a saturable value for the first and second spectral regimes, respectively.

关键词： Dispersion (waves) Nonlinear optics phase modulation Single mode fibers

Manipulation of Surface Plasmon Polaritons by phase modulation of Source Field with Inverse Problem Algorithm

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Chinese Physics Letters 2014年第5期31卷 152-156页

作者：刘春香梁国涛张美娜李振华程传福 College of Physics and Electronics Shandong Normal University Jinan 250014 Qilu University of Technology Jinan 250353

The predetermined field distributions can be achieved the propagation of surface plasmon polaritons （SPPs） by phase modulation of the source field to manipulate The modulations of the radius of the circular slit are according to the phase distributions on the slit, which are calculated by using the Gerchberg Saxton algorithm with the known field. We design the surface geometric shape of the radius-varied circular slit for exciting the SPP field with the linear, triangular, square and circular distribution characteristics, respectively. The slit structure designed for the circular field distribution is a plasmonic vortex lens that can be used to generate the vortex with the specified size of the primary ring, which shows that this heuristic method has the potential to devise plasmonic devices.

关键词： phase modulation

Tunable optical comb generation based on carrier-suppressed intensity modulation and phase modulation

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Chinese Optics Letters 2010年第5期8卷 468-470页

作者：邹喜华潘炜 Center for Information Photonics and Communications Southwest Jiaotong University Microwave Photonics Research Laboratory University of OttawaON K1N 6N5Canada

An approach to generate a flat optical comb with tunable comb spacing and adjustable comb number is proposed.In the proposed approach,a Mach-Zehnder modulator（MZM）,being biased to generate two carrier-suppressed first-order sidebands,is cascaded with a phase modulator.The two optical sidebands are then sent to the phase modulator to generate two identical,but frequency-shifted phase-modulated spectra.Thanks to the complementary nature of the two adjacent comb lines in the phase-modulated spectra,the overlapping of the two spectra would lead to the generation of a flat optical comb.Since only the phase modulation index or the microwave power is needed to be adjusted,the system is easy to be implemented with tunable comb spacing and adjustable comb number.Numerical simulations are performed,and the approach is verified by an experiment.

关键词： Computer simulation phase modulation

modulation instability induced by cross-phase modulation with the fourth-order dispersion in dispersion-decreasing fiber

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Chinese Optics Letters 2013年第7期11卷 13-17页

作者：胡涛平孙小菡 National Research Center for Optical Sensing/Communications Integrated Networking Lab of Photonics and Optical Communications Department of Electronic Engineering Southeast University College of Science Nanjing Forestry University

The modulation instability （MI） induced by cross-phase modulation （XPM） in dispersion-decreasing fiber （DDF）, whose dispersion decreases along the direction of propagation, is solved and analyzed by the pertur- bation method for the extended nonlinear SchrSdinger equation, considering the higher-order dispersion. The change of the gain spectra with incident power and dispersion decaying factor are also given respec- tively. Due to the fourth-order dispersion, XPM occurs at two gain spectral regions in both the normal and the anomalous dispersion regimes of DDF. The two gain spectral regions in the anomalous dispersion regime are larger than those in the normal dispersion ond region in the anomalous dispersion regime is near regime. Moreover, the gain spectrum of the sec- zero compared with that in the normal dispersion regime, indicating that XPM can be easily produced in the anomalous dispersion regime. The spectral width increases with the increase of the incident optical power and the dispersion decaying factor.

关键词： Nonlinear equations phase modulation