Life education is the precondition of all education.This paper explored the current situation of life education for college students in local normal colleges and universities through questionnaire survey,and traced th...Life education is the precondition of all education.This paper explored the current situation of life education for college students in local normal colleges and universities through questionnaire survey,and traced the history of life education in the world and China.Combined with history and reality,it analyzed the current problems of life education for college students mainly in three aspects,namely,the lack of connectivity in the educational process,the excessive productization of education,and the fragmentation of life education.Finally,it came up with pertinent recommendations in line with these problems.展开更多
Integrated 2-dimensional(2D)photonic devices such as monolayer waveguide has generated exceptional interest because of their ultimate thinness.In particular,they potentially permit stereo photonic architecture through...Integrated 2-dimensional(2D)photonic devices such as monolayer waveguide has generated exceptional interest because of their ultimate thinness.In particular,they potentially permit stereo photonic architecture through bond-free van der Waals integration.However,little is known about the coupling and controlling of the single-atom guided wave to its photonic environment,which governs the design and application of integrated system.Here,we report the optical coupling of atomically guided waves to other photonic modes.We directly probe the mode beating between evanescent waves in a monolayer 2D waveguide and a silicon photonic waveguide,which constitutes a vertically integrated interferometer.The mode-coupling measures the dispersion relation of the guided wave inside the atomic waveguide and unveils it strongly modifies matter's electronic states,manifesting by the formation of a propagating polariton.We also demonstrated light modulating and spectral detecting in this compact nonplanar interferometer.These findings provide a generalizable and versatile platform toward monolithic 3-dimensional integrated photonics.展开更多
The fiber-based saturable absorber(SA)that enables mode-locking within a ring cavity serves as the core component of the ultrafast all-fiber lasers.However,the integration of SAs onto fibers with high compactness suff...The fiber-based saturable absorber(SA)that enables mode-locking within a ring cavity serves as the core component of the ultrafast all-fiber lasers.However,the integration of SAs onto fibers with high compactness suffers from imbalanced saturable absorption properties and unstable mode-locking performance.Here,we present a robust mode-locking SA by integrating a nanocavity composed of a two-dimensional graphene heterostructure on the fiber end facet.We demonstrate a significant reduction in the saturation intensity(~65%)and improved soliton dynamic processes through precise modulation of the optical field within the heterostructure.The designed heterostructure facilitates the formation of a stable single-soliton state for robust mode-locking.A high tolerance to intracavity polarization variations is achieved in the heterostructure-SA(~85%compared to 20%for bare graphene).Our designed heterostructure-SA represents an important advancement in the development of ultracompact mode-locked all-fiber lasers,offering enhanced integrability and stability.展开更多
We report an ultrafast laser mode-locked with a graphene saturable absorber.The linear dispersions of the Dirac electrons in graphene enable wideband tunability.We get-1 ps pulses,tunable between 1525 and 1559 nm,with...We report an ultrafast laser mode-locked with a graphene saturable absorber.The linear dispersions of the Dirac electrons in graphene enable wideband tunability.We get-1 ps pulses,tunable between 1525 and 1559 nm,with stable mode-locking,insensitive to environmental perturbations.展开更多
Graphene is being actively explored as a candidate material for flexible and stretchable devices. However, the development of graphene-based flexible photonic devices, i.e. photodetectors, is hindered by the low absor...Graphene is being actively explored as a candidate material for flexible and stretchable devices. However, the development of graphene-based flexible photonic devices, i.e. photodetectors, is hindered by the low absorbance of the single layer of carbon atoms. Recently, van der Waals bonded carbon nanotube and graphene hybrid films have demonstrated excellent photoresponsivity, and the use of vein-like carbon nanotube networks resulted in significantly higher mechanical strength. Here, we report for the first time, a flexible photodetector with a high photoresponsivity of - 51 A/W and a fast response time of - 40 ms over the visible range, revealing the unique potential of this emerging all-carbon hybrid films for flexible devices. In addition, the device exhibits good robustness against repetitive bending, suggesting its applicability in large-area matrix-array flexible photodetectors.展开更多
Ultrafast fiber sources having short pulses, broad bandwidth, high energy, and low amplitude fluctuations have widespread applications. Stretched-pulse fiber lasers, incorporating segments of normal and anomalous disp...Ultrafast fiber sources having short pulses, broad bandwidth, high energy, and low amplitude fluctuations have widespread applications. Stretched-pulse fiber lasers, incorporating segments of normal and anomalous dispersion fibers, are a preferred means to generate such pulses. We realize a stretched-pulse fiber laser based on a nanotube saturable absorber, with 113 fs pulses, 33.5 nm spectral width and ~0.07% amplitude fluctuation, outperforming current nanotube-based designs.展开更多
Mid-infrared （mid-IR） （2-20 μm） photonics has numerous chemical and biologic ＂fingerprint＂ sensing applications due to characteristic vibrational transitions of molecules in the mid-IR spectral region. Unfortun...Mid-infrared （mid-IR） （2-20 μm） photonics has numerous chemical and biologic ＂fingerprint＂ sensing applications due to characteristic vibrational transitions of molecules in the mid-IR spectral region. Unfortunately, compared to visible light and telecommunication band wavelengths, photonic devices and applications have been difficult to develop at mid-IR wavelengths because of the intrinsic limitation of conventional materials. Breaking a new ground in the mid-IR science and technology calls for revolutionary materials. Graphene, a single atom layer of carbon arranged in a honey-comb lattice, has various promising optical and electrical properties because of its linear dispersion band structure and zero band gap features. In this review article, we discuss recent research develop- ments on mid-IR graphene photonics, in particular ultrafast lasers and photodetectors. Graphene-photonics-based biochemical applications, such as plasmonic sensing, photo- dynamic therapy, and florescence imaging are also reviewed.展开更多
Due to strong Coulomb interactions,two-dimensional(2D)semiconductors can support excitons with large binding energies and complex many-particle states.Their strong light-matter coupling and emerging excitonic phenomen...Due to strong Coulomb interactions,two-dimensional(2D)semiconductors can support excitons with large binding energies and complex many-particle states.Their strong light-matter coupling and emerging excitonic phenomena make them potential candidates for next-generation optoelectronic and valleytronic devices.The relaxation dynamics of optically excited states are a key ingredient of excitonic physics and directly impact the quantum efficiency and operating bandwidth of most photonic devices.Here,we summarize recent efforts in probing and modulating the photocarrier relaxation dynamics in 2D semiconductors.We classify these results according to the relaxation pathways or mechanisms they are associated with.The approaches discussed include both tailoring sample properties,such as the defect distribution and band structure,and applying external stimuli such as electric fields and mechanical strain.Particular emphasis is placed on discussing how the unique features of 2D semiconductors,including enhanced Coulomb interactions,sensitivity to the surrounding environment,flexible van der Waals(vdW)heterostructure construction,and non-degenerate valley/spin index of 2D transition metal dichalcogenides(TMDs),manifest themselves during photocarrier relaxation and how they can be manipulated.The extensive physical mechanisms that can be used to modulate photocarrier relaxation dynamics are instrumental for understanding and utilizing excitonic states in 2D semiconductors.展开更多
基金Supported by 2021 School-level Scientific Research Project of Chengdu Normal University"Research on the Value-level Practice Path of College Students'Life Education in the New Era"(CS21SCY18)Student's Platform for Innovation and Entrepreneurship Training Program at the State Level of the Ministry of Education(202114389038).
文摘Life education is the precondition of all education.This paper explored the current situation of life education for college students in local normal colleges and universities through questionnaire survey,and traced the history of life education in the world and China.Combined with history and reality,it analyzed the current problems of life education for college students mainly in three aspects,namely,the lack of connectivity in the educational process,the excessive productization of education,and the fragmentation of life education.Finally,it came up with pertinent recommendations in line with these problems.
基金supported by the National Natural Science Foundation of China(62325404,61934004,and 91950119)the Fundamental Research Funds for the Central Universities(021014380174)+1 种基金L.S.acknowledges the support from the Pearl River Talent Recruitment Program(2019QN01C216)Shenzhen Science and Technology Program(JCYJ20210324140805014)。
文摘Integrated 2-dimensional(2D)photonic devices such as monolayer waveguide has generated exceptional interest because of their ultimate thinness.In particular,they potentially permit stereo photonic architecture through bond-free van der Waals integration.However,little is known about the coupling and controlling of the single-atom guided wave to its photonic environment,which governs the design and application of integrated system.Here,we report the optical coupling of atomically guided waves to other photonic modes.We directly probe the mode beating between evanescent waves in a monolayer 2D waveguide and a silicon photonic waveguide,which constitutes a vertically integrated interferometer.The mode-coupling measures the dispersion relation of the guided wave inside the atomic waveguide and unveils it strongly modifies matter's electronic states,manifesting by the formation of a propagating polariton.We also demonstrated light modulating and spectral detecting in this compact nonplanar interferometer.These findings provide a generalizable and versatile platform toward monolithic 3-dimensional integrated photonics.
基金supported by the National Natural Science Foundation of China(12422406,12427806,T2188101,52025023,and 12374167)National Key R&D Program of China(2022YFA1403500 and 2021YFA1400201)the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘The fiber-based saturable absorber(SA)that enables mode-locking within a ring cavity serves as the core component of the ultrafast all-fiber lasers.However,the integration of SAs onto fibers with high compactness suffers from imbalanced saturable absorption properties and unstable mode-locking performance.Here,we present a robust mode-locking SA by integrating a nanocavity composed of a two-dimensional graphene heterostructure on the fiber end facet.We demonstrate a significant reduction in the saturation intensity(~65%)and improved soliton dynamic processes through precise modulation of the optical field within the heterostructure.The designed heterostructure facilitates the formation of a stable single-soliton state for robust mode-locking.A high tolerance to intracavity polarization variations is achieved in the heterostructure-SA(~85%compared to 20%for bare graphene).Our designed heterostructure-SA represents an important advancement in the development of ultracompact mode-locked all-fiber lasers,offering enhanced integrability and stability.
基金We acknowledge funding from a Royal Society Brian Mercer Award for Innovation,the European Research Council(ERC)grant NANOPOTS,Engineering and Physical Sciences Research Council(EPSRC)grants(Nos.EP/GO30480/1 and EP/G042357/1),King’s College and Imperial College.
文摘We report an ultrafast laser mode-locked with a graphene saturable absorber.The linear dispersions of the Dirac electrons in graphene enable wideband tunability.We get-1 ps pulses,tunable between 1525 and 1559 nm,with stable mode-locking,insensitive to environmental perturbations.
文摘Graphene is being actively explored as a candidate material for flexible and stretchable devices. However, the development of graphene-based flexible photonic devices, i.e. photodetectors, is hindered by the low absorbance of the single layer of carbon atoms. Recently, van der Waals bonded carbon nanotube and graphene hybrid films have demonstrated excellent photoresponsivity, and the use of vein-like carbon nanotube networks resulted in significantly higher mechanical strength. Here, we report for the first time, a flexible photodetector with a high photoresponsivity of - 51 A/W and a fast response time of - 40 ms over the visible range, revealing the unique potential of this emerging all-carbon hybrid films for flexible devices. In addition, the device exhibits good robustness against repetitive bending, suggesting its applicability in large-area matrix-array flexible photodetectors.
基金We acknowledge F.Hennrich for providing SWNTs and funding from a Royal Society Brian Mercer Award for Innovation,King’s College,Cambridge,ERC grant NANOPOTS,and EPSRC grant EP/G030480/1.
文摘Ultrafast fiber sources having short pulses, broad bandwidth, high energy, and low amplitude fluctuations have widespread applications. Stretched-pulse fiber lasers, incorporating segments of normal and anomalous dispersion fibers, are a preferred means to generate such pulses. We realize a stretched-pulse fiber laser based on a nanotube saturable absorber, with 113 fs pulses, 33.5 nm spectral width and ~0.07% amplitude fluctuation, outperforming current nanotube-based designs.
文摘Mid-infrared （mid-IR） （2-20 μm） photonics has numerous chemical and biologic ＂fingerprint＂ sensing applications due to characteristic vibrational transitions of molecules in the mid-IR spectral region. Unfortunately, compared to visible light and telecommunication band wavelengths, photonic devices and applications have been difficult to develop at mid-IR wavelengths because of the intrinsic limitation of conventional materials. Breaking a new ground in the mid-IR science and technology calls for revolutionary materials. Graphene, a single atom layer of carbon arranged in a honey-comb lattice, has various promising optical and electrical properties because of its linear dispersion band structure and zero band gap features. In this review article, we discuss recent research develop- ments on mid-IR graphene photonics, in particular ultrafast lasers and photodetectors. Graphene-photonics-based biochemical applications, such as plasmonic sensing, photo- dynamic therapy, and florescence imaging are also reviewed.
基金supported in part by the State Key Project of Research and Development of China(2018YFB2200500,2017YFA0206304)National Natural Science Foundation of China(61775093,61427812,61804074)+2 种基金National Youth 1000-Talent Plan‘Jiangsu Shuangchuang Team’ProgramNatural Science Foundation of Jiangsu Province(BK20170012).
文摘Due to strong Coulomb interactions,two-dimensional(2D)semiconductors can support excitons with large binding energies and complex many-particle states.Their strong light-matter coupling and emerging excitonic phenomena make them potential candidates for next-generation optoelectronic and valleytronic devices.The relaxation dynamics of optically excited states are a key ingredient of excitonic physics and directly impact the quantum efficiency and operating bandwidth of most photonic devices.Here,we summarize recent efforts in probing and modulating the photocarrier relaxation dynamics in 2D semiconductors.We classify these results according to the relaxation pathways or mechanisms they are associated with.The approaches discussed include both tailoring sample properties,such as the defect distribution and band structure,and applying external stimuli such as electric fields and mechanical strain.Particular emphasis is placed on discussing how the unique features of 2D semiconductors,including enhanced Coulomb interactions,sensitivity to the surrounding environment,flexible van der Waals(vdW)heterostructure construction,and non-degenerate valley/spin index of 2D transition metal dichalcogenides(TMDs),manifest themselves during photocarrier relaxation and how they can be manipulated.The extensive physical mechanisms that can be used to modulate photocarrier relaxation dynamics are instrumental for understanding and utilizing excitonic states in 2D semiconductors.
