None He Xiao-An, None Yang Jia-Min, None Li Yu-Kun, None Li Jin, None Xiong gang
CsI photocathode's response sensitivity is an important parameter for the quantitative diagnosis of X-ray spectroscopy by soft X-ray streak camera, and its theoretical calculation has important guiding significance. The current theoretical analytical model are based on the one-dimensional random walking model of secondary electrons generated by thin film photocathodes, including the Henke model under the condition of normal incidence of X-rays and energy greater than 1keV, and the Fraser model under variable angle incidence and photocathode thickness greater than 100nm, which have certain limitations. In this paper, the basic expression of the probability of secondary electron transmission are introduced, and the general expression of the response sensitivity of CsI photocathode are deduced in a larger parameter range (X-ray energy 0.1-10keV, photocathode thickness 10-200nm) varies with X-ray energy E, photocathode thickness t, and the angle θ between X-ray and cathode surface. Finally, the theoretical calculation results of this paper are compare and discussed with the Henke model, Fraser model, literature data and experimental data on Beijing synchrotron radiation facility, which verifies the accuracy and universality of the computational model, and a theoretical reference is provided for the optimal design of CsI photocathode in high-time-resolution spectrometric quantitative measurement.
{"title":"Theoretical calculation of CsI photocathode’s response sensitivity of soft X-ray streak camera","authors":"None He Xiao-An, None Yang Jia-Min, None Li Yu-Kun, None Li Jin, None Xiong gang","doi":"10.7498/aps.72.20231043","DOIUrl":"https://doi.org/10.7498/aps.72.20231043","url":null,"abstract":"CsI photocathode's response sensitivity is an important parameter for the quantitative diagnosis of X-ray spectroscopy by soft X-ray streak camera, and its theoretical calculation has important guiding significance. The current theoretical analytical model are based on the one-dimensional random walking model of secondary electrons generated by thin film photocathodes, including the Henke model under the condition of normal incidence of X-rays and energy greater than 1keV, and the Fraser model under variable angle incidence and photocathode thickness greater than 100nm, which have certain limitations. In this paper, the basic expression of the probability of secondary electron transmission are introduced, and the general expression of the response sensitivity of CsI photocathode are deduced in a larger parameter range (X-ray energy 0.1-10keV, photocathode thickness 10-200nm) varies with X-ray energy E, photocathode thickness t, and the angle θ between X-ray and cathode surface. Finally, the theoretical calculation results of this paper are compare and discussed with the Henke model, Fraser model, literature data and experimental data on Beijing synchrotron radiation facility, which verifies the accuracy and universality of the computational model, and a theoretical reference is provided for the optimal design of CsI photocathode in high-time-resolution spectrometric quantitative measurement.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136202530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
None Zhang Shan-Liang, None Xing Hongxi, None Wang Enke
One of the main goals of high-energy nuclear physics is to explore the fundamental properties of quark-gluon plasma (QGP), a new state of quantum chromodynamics (QCD) matter created in relativistic heavy-ion collisions, in which the energetic quarks and gluons, known as fast partons, created prior to the formation of the QGP, traverse the hot-dense medium and experience strong interactions with the constituents of the medium, and eventually lead to the attenuation of jet energy. Such a novel phenomenon, referred to as jet quenching, plays an essential role in probing the transport properties of the QGP. The objective of this paper is to review some of the latest experimental and theoretical progress of jet quenching, such as medium modification on the large begin{document}$ p_{rm T} $end{document} hadrons, full jets, and jet substructures in heavy-ion collisions, as well as the challenges in the forefront theoretical investigations.
One of the main goals of high-energy nuclear physics is to explore the fundamental properties of quark-gluon plasma (QGP), a new state of quantum chromodynamics (QCD) matter created in relativistic heavy-ion collisions, in which the energetic quarks and gluons, known as fast partons, created prior to the formation of the QGP, traverse the hot-dense medium and experience strong interactions with the constituents of the medium, and eventually lead to the attenuation of jet energy. Such a novel phenomenon, referred to as jet quenching, plays an essential role in probing the transport properties of the QGP. The objective of this paper is to review some of the latest experimental and theoretical progress of jet quenching, such as medium modification on the large <inline-formula><tex-math id="M11111">begin{document}$ p_{rm T} $end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="20-20230993_M11111.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="20-20230993_M11111.png"/></alternatives></inline-formula> hadrons, full jets, and jet substructures in heavy-ion collisions, as well as the challenges in the forefront theoretical investigations.
{"title":"Jet quenching in heavy-ion collisions","authors":"None Zhang Shan-Liang, None Xing Hongxi, None Wang Enke","doi":"10.7498/aps.72.20230993","DOIUrl":"https://doi.org/10.7498/aps.72.20230993","url":null,"abstract":"One of the main goals of high-energy nuclear physics is to explore the fundamental properties of quark-gluon plasma (QGP), a new state of quantum chromodynamics (QCD) matter created in relativistic heavy-ion collisions, in which the energetic quarks and gluons, known as fast partons, created prior to the formation of the QGP, traverse the hot-dense medium and experience strong interactions with the constituents of the medium, and eventually lead to the attenuation of jet energy. Such a novel phenomenon, referred to as jet quenching, plays an essential role in probing the transport properties of the QGP. The objective of this paper is to review some of the latest experimental and theoretical progress of jet quenching, such as medium modification on the large <inline-formula><tex-math id=\"M11111\">begin{document}$ p_{rm T} $end{document}</tex-math><alternatives><graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"20-20230993_M11111.jpg\"/><graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"20-20230993_M11111.png\"/></alternatives></inline-formula> hadrons, full jets, and jet substructures in heavy-ion collisions, as well as the challenges in the forefront theoretical investigations.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136202955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lithium niobate, known as one of the most widely used nonlinear optical crystals, has recently received significant attention from both academia and industrial circles. The surge in interest can be attributed to the commercial availability of thin-film lithium niobate (TFLN) wafers and the rapid advancements in nanofabrication techniques. A milestone was achieved in 2020 with the successful fabrication of wafer-scale TFLN photonic integrated circuits, which paved the way for mass-producible and cost-effective manufacturing of TFLN-based products.At present, the majority of research on TFLN photonic integrated devices focuses on light manipulation, i.e. field modulation and frequency conversion. The electro-optic, acousto-optic, photo-elastic and piezo-electric effects of lithium niobate are harnessed to modulate the amplitude, phase and frequency of light. The second-order and third-order nonlinearities of lithium niobate enable frequency conversion processes, which leads to the development of frequency converters, optical frequency combs, and supercontinuum generation devices. These exceptional optical properties of lithium niobate enable the electromagnetic wave to manipulate covering from radio-frequency to terahertz, infrared, and visible bands. Using the outstanding performance of TFLN photonic integrated devices, including remarkable modulation rate, wide operation bandwidth, efficient nonlinear frequency conversion, and low power consumption, diverse applications, such as spanning optical information processing, laser ranging, optical frequency combs, microwave optics, precision measurement, quantum optics, and quantum computing, are demonstrated.Additionally, it is reported that TFLN-based lasers and amplifiers have made remarkable progress, and both optical and electrical pumps are available. These achievements include combining gain materials, such as rare-earth ions or heterostructures, with III-V semiconductors. The integration of low-dimensional materials or absorptive metals with TFLN can also realize TFLN-based detectors. These significant developments expand the potential applications of TFLN photonic integrated devices, thus paving the way for monolithic TFLN chips.The versatility and high performances of TFLN photonic integrated devices have made revolutionary progress in these fields, opening up new possibilities for cutting-edge technologies and their practical implementations. In this point of view, we briefly introduce the development of TFLN nanofabricationn technology. Subsequently, we review the latest progress of TFLN photonic integrated devices, including lasers, functional nonlinear optical devices, and detectors. Finally, we discuss the future development directions and potential ways of TFLN photonics.
{"title":"Thin-film lithium niobate photonic integrated devices: Progresses and opportunities","authors":"None Xiao Xiong, None Qi-Tao Cao, None Yun-Feng Xiao","doi":"10.7498/aps.72.20231295","DOIUrl":"https://doi.org/10.7498/aps.72.20231295","url":null,"abstract":"<sec>Lithium niobate, known as one of the most widely used nonlinear optical crystals, has recently received significant attention from both academia and industrial circles. The surge in interest can be attributed to the commercial availability of thin-film lithium niobate (TFLN) wafers and the rapid advancements in nanofabrication techniques. A milestone was achieved in 2020 with the successful fabrication of wafer-scale TFLN photonic integrated circuits, which paved the way for mass-producible and cost-effective manufacturing of TFLN-based products.</sec><sec>At present, the majority of research on TFLN photonic integrated devices focuses on light manipulation, i.e. field modulation and frequency conversion. The electro-optic, acousto-optic, photo-elastic and piezo-electric effects of lithium niobate are harnessed to modulate the amplitude, phase and frequency of light. The second-order and third-order nonlinearities of lithium niobate enable frequency conversion processes, which leads to the development of frequency converters, optical frequency combs, and supercontinuum generation devices. These exceptional optical properties of lithium niobate enable the electromagnetic wave to manipulate covering from radio-frequency to terahertz, infrared, and visible bands. Using the outstanding performance of TFLN photonic integrated devices, including remarkable modulation rate, wide operation bandwidth, efficient nonlinear frequency conversion, and low power consumption, diverse applications, such as spanning optical information processing, laser ranging, optical frequency combs, microwave optics, precision measurement, quantum optics, and quantum computing, are demonstrated.</sec><sec>Additionally, it is reported that TFLN-based lasers and amplifiers have made remarkable progress, and both optical and electrical pumps are available. These achievements include combining gain materials, such as rare-earth ions or heterostructures, with III-V semiconductors. The integration of low-dimensional materials or absorptive metals with TFLN can also realize TFLN-based detectors. These significant developments expand the potential applications of TFLN photonic integrated devices, thus paving the way for monolithic TFLN chips.</sec><sec>The versatility and high performances of TFLN photonic integrated devices have made revolutionary progress in these fields, opening up new possibilities for cutting-edge technologies and their practical implementations. In this point of view, we briefly introduce the development of TFLN nanofabricationn technology. Subsequently, we review the latest progress of TFLN photonic integrated devices, including lasers, functional nonlinear optical devices, and detectors. Finally, we discuss the future development directions and potential ways of TFLN photonics.</sec>","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135550689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Based on the current growth technology of quantum dot in the experiment, considering that the probe fields and control fields at different frequencies are coupled between different energy levels of the InAs/GaAs quantum dot, the ladder-type, Λ-type and V-type energy level configurations can be formed. The linear and nonlinear properties of these energy level configurations of InAs/GaAs quantum dots are studied by using semiclassical theory combined with multiple scale method. It is shown that in the linear case, electromagnetic induction transparency windows can be formed among ladder-type, Λ-type and V-type energy level configurations. And the width of the transparent window increases with the strength of the control pulse increasing. For the nonlinear case, under the current experimental condition, optical solitons can be formed and stored in ladder-type configuration and begin{document}$ {{Lambda }} $end{document}-type energy level configuration. However, optical solitons cannot be formed in the V-type energy level configurations, which is because the nonlinear effect of the system is very weak. Furthermore, it is demonstrated that the fidelity of the storage and retrieval of the optical solitons is higher than that of linear optical pulse and strongly nonlinear optical pulse. Interestingly, it is also found that the amplitude of stored optical solitons in begin{document}$ {{Lambda }} $end{document}-type energy level configuration is higher than that in ladder-type energy level configuration. This study provides a theoretical basis for semiconductor quantum dot devices to modulate the amplitude of the stored optical solitons.
Based on the current growth technology of quantum dot in the experiment, considering that the probe fields and control fields at different frequencies are coupled between different energy levels of the InAs/GaAs quantum dot, the ladder-type, Λ-type and V-type energy level configurations can be formed. The linear and nonlinear properties of these energy level configurations of InAs/GaAs quantum dots are studied by using semiclassical theory combined with multiple scale method. It is shown that in the linear case, electromagnetic induction transparency windows can be formed among ladder-type, Λ-type and V-type energy level configurations. And the width of the transparent window increases with the strength of the control pulse increasing. For the nonlinear case, under the current experimental condition, optical solitons can be formed and stored in ladder-type configuration and <inline-formula><tex-math id="M6">begin{document}$ {{Lambda }} $end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="8-20221965_M6.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="8-20221965_M6.png"/></alternatives></inline-formula>-type energy level configuration. However, optical solitons cannot be formed in the V-type energy level configurations, which is because the nonlinear effect of the system is very weak. Furthermore, it is demonstrated that the fidelity of the storage and retrieval of the optical solitons is higher than that of linear optical pulse and strongly nonlinear optical pulse. Interestingly, it is also found that the amplitude of stored optical solitons in <inline-formula><tex-math id="M8">begin{document}$ {{Lambda }} $end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="8-20221965_M8.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="8-20221965_M8.png"/></alternatives></inline-formula>-type energy level configuration is higher than that in ladder-type energy level configuration. This study provides a theoretical basis for semiconductor quantum dot devices to modulate the amplitude of the stored optical solitons.
{"title":"Effect of energy level configuration on storage of optical solitons in InAs/GaAs quantum dot electromagnetically induced transparency medium","authors":"Yin Wang, Si-Jie Zhou, Qiao Chen, Yong-He Deng","doi":"10.7498/aps.72.20221965","DOIUrl":"https://doi.org/10.7498/aps.72.20221965","url":null,"abstract":"Based on the current growth technology of quantum dot in the experiment, considering that the probe fields and control fields at different frequencies are coupled between different energy levels of the InAs/GaAs quantum dot, the ladder-type, Λ-type and V-type energy level configurations can be formed. The linear and nonlinear properties of these energy level configurations of InAs/GaAs quantum dots are studied by using semiclassical theory combined with multiple scale method. It is shown that in the linear case, electromagnetic induction transparency windows can be formed among ladder-type, Λ-type and V-type energy level configurations. And the width of the transparent window increases with the strength of the control pulse increasing. For the nonlinear case, under the current experimental condition, optical solitons can be formed and stored in ladder-type configuration and <inline-formula><tex-math id=\"M6\">begin{document}$ {{Lambda }} $end{document}</tex-math><alternatives><graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"8-20221965_M6.jpg\"/><graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"8-20221965_M6.png\"/></alternatives></inline-formula>-type energy level configuration. However, optical solitons cannot be formed in the V-type energy level configurations, which is because the nonlinear effect of the system is very weak. Furthermore, it is demonstrated that the fidelity of the storage and retrieval of the optical solitons is higher than that of linear optical pulse and strongly nonlinear optical pulse. Interestingly, it is also found that the amplitude of stored optical solitons in <inline-formula><tex-math id=\"M8\">begin{document}$ {{Lambda }} $end{document}</tex-math><alternatives><graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"8-20221965_M8.jpg\"/><graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"8-20221965_M8.png\"/></alternatives></inline-formula>-type energy level configuration is higher than that in ladder-type energy level configuration. This study provides a theoretical basis for semiconductor quantum dot devices to modulate the amplitude of the stored optical solitons.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134996511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vortex beams have attracted extensive attention in recent decade due to the carried optical orbital angular momentum (OAM). Vortex beams carrying different OAM modes are orthogonal to each other, and thus have become highly promising in realizing high-capacity optical communication systems. This review is to introduce the fundamental principles of optical OAM mode demultiplexing, recent advances in the fabrication techniques and emerging applications in high-capacity optical communications. First, this review introduces the development history of the working principle of OAM mode demultiplexer. Subsequently, a variety of preparation techniques and emerging applications of OAM mode demultiplexing are discussed in detail. Finally, we provide an in-depth analysis and outlook for the future trends and prospects of the OAM mode demultiplexer.
{"title":"Miniaturized optical vortex mode demultiplexer: Principle, fabrication and applications","authors":"None Xinyu Yang, None Huapeng Ye, None Peiyun Li, None Helin Liao, None Dong Yuan, None Guofu Zhou","doi":"10.7498/aps.72.20231521","DOIUrl":"https://doi.org/10.7498/aps.72.20231521","url":null,"abstract":"Vortex beams have attracted extensive attention in recent decade due to the carried optical orbital angular momentum (OAM). Vortex beams carrying different OAM modes are orthogonal to each other, and thus have become highly promising in realizing high-capacity optical communication systems. This review is to introduce the fundamental principles of optical OAM mode demultiplexing, recent advances in the fabrication techniques and emerging applications in high-capacity optical communications. First, this review introduces the development history of the working principle of OAM mode demultiplexer. Subsequently, a variety of preparation techniques and emerging applications of OAM mode demultiplexing are discussed in detail. Finally, we provide an in-depth analysis and outlook for the future trends and prospects of the OAM mode demultiplexer.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136260017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
None Zhang Zhi-Yu, None Zhao Yang, None Qing Bo, None Zhang Ji-Yan, None Ma Jian-Yi, None Lin Cheng-Liang, None Yang Guo-Hong, None Wei Min-Xi, None Xiong Gang, None Lv Min, None Huang Cheng-Wu, None Zhu Tuo, None Song Tian-Ming, None Zhao Yan, None Zhang Yu-Xue, None Zhang Lu, None Li Li-Ling, None Du Hua-Bing, None Che Xing-Sen, None Li Yu-Kun, None Zan Xia-Yu, None Yang Jia-Min
Warm dense matter (WDM), a state of matter which lies at the frontiers between condensed matter and plasma, is one of the main research objects of high energy density physics (HEDP). Compared to the isolated atom, the electron structure of WDM will change because of the influence of density and temperature effect. Since WDM is always strongly coupled and partially degenerated, the precise theoretical description is very complex and accurate experimental studies are also very challenging. In this paper, a study of the density effect on the warm dense matter electron structure based on the x-ray fluorescence spectroscopy is presented. In the experiment, warm dense titanium with density larger than solid density is created based on a special designed hohlraum. Then, using the characteristic line spectrum emitted by the laser irradiation on pump material (Vanadium) as pump source, the titanium will emit fluorescence. The x-ray fluorescence spectroscopy of titanium with different states is diagnosed by changing the delay time between the pump laser and drive laser. The experimental fluorescence spectrum indicates that the energy difference between Kβ and Kα (Kβ-Kα) of the compressed titanium (7.2~9.2 g/cm3, 1.6~2.4 eV) is about 2 eV smaller than that of cold titanium. Two theoretical methods, finite-temperature relativistic density functional theory (FTRDFT) and two-step Hartree-Fock-Slater (TSHFS), are used to calculate the fluorescence spectrum of warm dense titanium. The calculated results indicate that the energy difference (Kβ-Kα) will decrease with density but change slowly with temperature during the calculated state (4.5~13.5 g/cm3、 0.03~5 eV). FTRDFT overestimates the density effect on the line shift, while TSHFS underestimates the density effect. The future work will focus on optimizing the experimental method of x-ray fluorescence spectroscopy, obtaining x-ray fluorescence spectrum of titanium with more state, and then testing the theoretical method for warm dense matter.
{"title":"Density effect on electronic structure of warm dense matter based on x-ray fluorescence spectroscopy","authors":"None Zhang Zhi-Yu, None Zhao Yang, None Qing Bo, None Zhang Ji-Yan, None Ma Jian-Yi, None Lin Cheng-Liang, None Yang Guo-Hong, None Wei Min-Xi, None Xiong Gang, None Lv Min, None Huang Cheng-Wu, None Zhu Tuo, None Song Tian-Ming, None Zhao Yan, None Zhang Yu-Xue, None Zhang Lu, None Li Li-Ling, None Du Hua-Bing, None Che Xing-Sen, None Li Yu-Kun, None Zan Xia-Yu, None Yang Jia-Min","doi":"10.7498/aps.72.20231215","DOIUrl":"https://doi.org/10.7498/aps.72.20231215","url":null,"abstract":"Warm dense matter (WDM), a state of matter which lies at the frontiers between condensed matter and plasma, is one of the main research objects of high energy density physics (HEDP). Compared to the isolated atom, the electron structure of WDM will change because of the influence of density and temperature effect. Since WDM is always strongly coupled and partially degenerated, the precise theoretical description is very complex and accurate experimental studies are also very challenging. In this paper, a study of the density effect on the warm dense matter electron structure based on the x-ray fluorescence spectroscopy is presented. In the experiment, warm dense titanium with density larger than solid density is created based on a special designed hohlraum. Then, using the characteristic line spectrum emitted by the laser irradiation on pump material (Vanadium) as pump source, the titanium will emit fluorescence. The x-ray fluorescence spectroscopy of titanium with different states is diagnosed by changing the delay time between the pump laser and drive laser. The experimental fluorescence spectrum indicates that the energy difference between Kβ and Kα (Kβ-Kα) of the compressed titanium (7.2~9.2 g/cm<sup>3</sup>, 1.6~2.4 eV) is about 2 eV smaller than that of cold titanium. Two theoretical methods, finite-temperature relativistic density functional theory (FTRDFT) and two-step Hartree-Fock-Slater (TSHFS), are used to calculate the fluorescence spectrum of warm dense titanium. The calculated results indicate that the energy difference (Kβ-Kα) will decrease with density but change slowly with temperature during the calculated state (4.5~13.5 g/cm<sup>3</sup>、 0.03~5 eV). FTRDFT overestimates the density effect on the line shift, while TSHFS underestimates the density effect. The future work will focus on optimizing the experimental method of x-ray fluorescence spectroscopy, obtaining x-ray fluorescence spectrum of titanium with more state, and then testing the theoretical method for warm dense matter.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135400194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For discrete optical systems integrated into optical fibers, the optical fields of the individual waveguides are coupled and correlated with each other. This paper investigates how the refractive index of discrete waveguides can be tuned by thermal diffusion to enhance the coupling between discrete waveguides. In this paper, the discrete waveguide thermally diffused model and the thermally diffused coupling model of twin-core and three-core fibers are constructed. The multicore fiber is heated with a hydrogen-oxygen flame for different times, and the outgoing light field at the end face of the optical fiber is monitored at the same time. Then, the three-dimensional refractive index measurement results of the thermally diffused multicore fiber verify the feasibility of thermal diffusion technology to change the refractive index of discrete waveguides for coupling. Thermal diffusion technology can be used to fabricate multicore fiber couplers. Combined with multicore fiber and core-by-core inscribed fiber Bragg gratings technology, single-channel sensing measurement can be realized by thermal diffusion technology. The method of changing the refractive index of discrete waveguides through thermal diffusion has the advantages of high integration, high stability, and mass fabrication. The research on the thermal diffusion of discrete waveguides can improve the application potential of multicore fiber sensing systems, and promote the broad application of discrete waveguide structure optical fiber in the fields of optical communication, optical sensing, biomedicine, artificial intelligence.
{"title":"Thermal diffusion coupling mechanism and its application of discrete waveguide","authors":"None Meng Ling-Zhi, None Yuan Li-Bo","doi":"10.7498/aps.72.20230204","DOIUrl":"https://doi.org/10.7498/aps.72.20230204","url":null,"abstract":"For discrete optical systems integrated into optical fibers, the optical fields of the individual waveguides are coupled and correlated with each other. This paper investigates how the refractive index of discrete waveguides can be tuned by thermal diffusion to enhance the coupling between discrete waveguides. In this paper, the discrete waveguide thermally diffused model and the thermally diffused coupling model of twin-core and three-core fibers are constructed. The multicore fiber is heated with a hydrogen-oxygen flame for different times, and the outgoing light field at the end face of the optical fiber is monitored at the same time. Then, the three-dimensional refractive index measurement results of the thermally diffused multicore fiber verify the feasibility of thermal diffusion technology to change the refractive index of discrete waveguides for coupling. Thermal diffusion technology can be used to fabricate multicore fiber couplers. Combined with multicore fiber and core-by-core inscribed fiber Bragg gratings technology, single-channel sensing measurement can be realized by thermal diffusion technology. The method of changing the refractive index of discrete waveguides through thermal diffusion has the advantages of high integration, high stability, and mass fabrication. The research on the thermal diffusion of discrete waveguides can improve the application potential of multicore fiber sensing systems, and promote the broad application of discrete waveguide structure optical fiber in the fields of optical communication, optical sensing, biomedicine, artificial intelligence.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135495613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chen Liao, Ning Yao, Lu-Ping Tang, Wei-Hua Shi, Shao-Ling Sun, Hao-Ran Yang
The development of colloidal near-infrared quantum dot (QD) lasers has been hindered by the high state degeneracy of lead salt QDs and the difficulty in coupling colloidal QDs to the resonant cavity. In this study, we show that the above challenges can be addressed by the self-assembly laser based on Ag2Se QDs. The Ag2Se QDs with the lowest quantized states 2-fold degeneracy are used to replace lead salt quantum dots to achieve low threshold near-infrared optical gain. We employ the finite element method to in depth analyze the mode field distribution and oscillation mechanism of the coffee-ring microcavity. Our results reveal that the light field oscillates in a zig-zag path along the cross-sectional area, indicating strong coupling between the QDs and the cavity mode. Furthermore, we investigate the relationship of cavity length with free spectrum range and laser emission wavelength. Using this relationship and the gain spectrum characteristics of Ag2Se QDs, we design a single-mode near-infrared laser and conduct a comprehensive analysis. The simulation results are used to fabricate a single-mode near-infrared Ag2Se QD coffee-ring microlaser, which exhibits a linewidth of 0.3 nm and a threshold of 158 μJ cm–2. Currently, it holds the record for the lowest laser threshold among near-infrared colloidal QD lasers. The increasing of the laser cavity length leads the emission wavelength to increase from 1300 nm to 1323 nm. In addition, the toxicity of Ag2Se QD is remarkably negligible. Our work promotes the development of environment-friendly near-infrared lasers toward practical lasers.
{"title":"Near-infrared self-assembled laser based on Ag<sub>2</sub>Se quantum dots","authors":"Chen Liao, Ning Yao, Lu-Ping Tang, Wei-Hua Shi, Shao-Ling Sun, Hao-Ran Yang","doi":"10.7498/aps.72.20231457","DOIUrl":"https://doi.org/10.7498/aps.72.20231457","url":null,"abstract":"The development of colloidal near-infrared quantum dot (QD) lasers has been hindered by the high state degeneracy of lead salt QDs and the difficulty in coupling colloidal QDs to the resonant cavity. In this study, we show that the above challenges can be addressed by the self-assembly laser based on Ag<sub>2</sub>Se QDs. The Ag<sub>2</sub>Se QDs with the lowest quantized states 2-fold degeneracy are used to replace lead salt quantum dots to achieve low threshold near-infrared optical gain. We employ the finite element method to in depth analyze the mode field distribution and oscillation mechanism of the coffee-ring microcavity. Our results reveal that the light field oscillates in a zig-zag path along the cross-sectional area, indicating strong coupling between the QDs and the cavity mode. Furthermore, we investigate the relationship of cavity length with free spectrum range and laser emission wavelength. Using this relationship and the gain spectrum characteristics of Ag<sub>2</sub>Se QDs, we design a single-mode near-infrared laser and conduct a comprehensive analysis. The simulation results are used to fabricate a single-mode near-infrared Ag<sub>2</sub>Se QD coffee-ring microlaser, which exhibits a linewidth of 0.3 nm and a threshold of 158 μJ cm<sup>–2</sup>. Currently, it holds the record for the lowest laser threshold among near-infrared colloidal QD lasers. The increasing of the laser cavity length leads the emission wavelength to increase from 1300 nm to 1323 nm. In addition, the toxicity of Ag<sub>2</sub>Se QD is remarkably negligible. Our work promotes the development of environment-friendly near-infrared lasers toward practical lasers.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135560204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
None Zhao Rui, None Shen Lai-Quan, None Chang Chao, None Bai Hai-Yang, None Wang Wei-Hua
Lunar glass, a significant component of lunar soil, is produced by non-equilibrium processes on the moon, such as volcanic eruptions, meteorite impacts, solar wind, and cosmic radiation. Lunar glass of different origins has ability to record historical information of the formation and evolution of the moon. This article presents a comprehensive review of the research progress of lunar glass found within the CE-5 lunar soil. Delving into its fundamental physical properties and microstructure, we explore the specific mechanismsbehind the formation of lunar glass. Furthermore, the investigation focuses on the diverse roles lunar glass plays in lunar evolution studies, such as acting as a “natural camera” that captures the moon's internal and surface changes over different epochs, encompassing lunar origin, magma activity, impact events, space weathering, and the origin of water. The ultra-stable lunar glass with disordered atomic structure can sustainably preserve lunar resources. It is worth noting that it is estimated that it has a substantial reserve of 3He, approximately 260,000 tons, and an astounding 27 billion tons of water. Moreover, lunar glass serves as an invaluable lunar chronometer, providing a reliable temporal framework for dating volcanic activity and impact events. This temporal framework, in turn, serves as a vital tool for investigating the evolution of lunar water, magnetic fields and reconstructing an extensive billion-year history of lunar impacts.
{"title":"Lunar Glasses","authors":"None Zhao Rui, None Shen Lai-Quan, None Chang Chao, None Bai Hai-Yang, None Wang Wei-Hua","doi":"10.7498/aps.72.20231238","DOIUrl":"https://doi.org/10.7498/aps.72.20231238","url":null,"abstract":"Lunar glass, a significant component of lunar soil, is produced by non-equilibrium processes on the moon, such as volcanic eruptions, meteorite impacts, solar wind, and cosmic radiation. Lunar glass of different origins has ability to record historical information of the formation and evolution of the moon. This article presents a comprehensive review of the research progress of lunar glass found within the CE-5 lunar soil. Delving into its fundamental physical properties and microstructure, we explore the specific mechanismsbehind the formation of lunar glass. Furthermore, the investigation focuses on the diverse roles lunar glass plays in lunar evolution studies, such as acting as a “natural camera” that captures the moon's internal and surface changes over different epochs, encompassing lunar origin, magma activity, impact events, space weathering, and the origin of water. The ultra-stable lunar glass with disordered atomic structure can sustainably preserve lunar resources. It is worth noting that it is estimated that it has a substantial reserve of <sup>3</sup>He, approximately 260,000 tons, and an astounding 27 billion tons of water. Moreover, lunar glass serves as an invaluable lunar chronometer, providing a reliable temporal framework for dating volcanic activity and impact events. This temporal framework, in turn, serves as a vital tool for investigating the evolution of lunar water, magnetic fields and reconstructing an extensive billion-year history of lunar impacts.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135400395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
None Zhou Yang, None Ma Xiao, None Zhou Xing-Yu, None Zhang Chun-Hui, None Wang Qin
Quantum key distribution (QKD) enables the establishment of shared keys between two distant users, Alice and Bob, based on the fundamental principles of quantum mechanics, and it has been proven to possess information-theoretic security. In most QKD systems, Alice and Bob require a shared reference frame, and real-time calibration of the reference frame increases system costs and reduces its performance. Fortunately, the reference-frame-independent QKD protocol has been proposed, overcoming reference-frame drift issues and receiving widespread attention. However, in practical QKD systems, the non-ideal characteristics of realistic devices introduce certain inconsistency between the theory and the practice. In real-world quantum key distribution systems, device imperfections can lead to security vulnerabilities, thereby reducing system security. For example, imperfections in the encoding apparatus at the source end may result in errors in the quantum states. The inherent defects in the detection part may cause after-pulse effects and dead-time effects, and decreasing the key rate. Therefore, in this paper, we propose a practical state-preparation error tolerant reference-frame-independent quantum key distribution protocol by taking imperfections in both the source and the detectors into account. Moreover, a three-intensity decoy-state scheme for modeling analysis and numerical simulations is employed. In this protocol, we reduce the impact of state-preparation errors on the key rate by utilizing virtual state methods to precisely estimate the phase-error rate. Furthermore, by characterizing the effects of after-pulses and dead-time on the key rate, our protocol exhibits higher robustness and can effectively address issues related to detector imperfections. This approach can also be extended to other quantum key distribution protocols with higher security levels, such as measurement-device-independent quantum key distribution protocol and twin-field quantum key distribution, further mitigating the influence of device imperfections on practical implementation of QKD systems. Therefore, our present work provide important reference value for the practical application of quantum key distributions.
{"title":"A Study of practical state-preparation error tolerant reference-frame-independent quantum key distribution protocol","authors":"None Zhou Yang, None Ma Xiao, None Zhou Xing-Yu, None Zhang Chun-Hui, None Wang Qin","doi":"10.7498/aps.72.20231144","DOIUrl":"https://doi.org/10.7498/aps.72.20231144","url":null,"abstract":"Quantum key distribution (QKD) enables the establishment of shared keys between two distant users, Alice and Bob, based on the fundamental principles of quantum mechanics, and it has been proven to possess information-theoretic security. In most QKD systems, Alice and Bob require a shared reference frame, and real-time calibration of the reference frame increases system costs and reduces its performance. Fortunately, the reference-frame-independent QKD protocol has been proposed, overcoming reference-frame drift issues and receiving widespread attention. However, in practical QKD systems, the non-ideal characteristics of realistic devices introduce certain inconsistency between the theory and the practice. In real-world quantum key distribution systems, device imperfections can lead to security vulnerabilities, thereby reducing system security. For example, imperfections in the encoding apparatus at the source end may result in errors in the quantum states. The inherent defects in the detection part may cause after-pulse effects and dead-time effects, and decreasing the key rate. Therefore, in this paper, we propose a practical state-preparation error tolerant reference-frame-independent quantum key distribution protocol by taking imperfections in both the source and the detectors into account. Moreover, a three-intensity decoy-state scheme for modeling analysis and numerical simulations is employed. In this protocol, we reduce the impact of state-preparation errors on the key rate by utilizing virtual state methods to precisely estimate the phase-error rate. Furthermore, by characterizing the effects of after-pulses and dead-time on the key rate, our protocol exhibits higher robustness and can effectively address issues related to detector imperfections. This approach can also be extended to other quantum key distribution protocols with higher security levels, such as measurement-device-independent quantum key distribution protocol and twin-field quantum key distribution, further mitigating the influence of device imperfections on practical implementation of QKD systems. Therefore, our present work provide important reference value for the practical application of quantum key distributions.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135596078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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