Two types of bound states in continuum(BICs),symmetry-protected and Brillouin zone folding driven,are identified in hollow Si nanorod arrays.By modulating the direction and distance of the air holes from the center of...Two types of bound states in continuum(BICs),symmetry-protected and Brillouin zone folding driven,are identified in hollow Si nanorod arrays.By modulating the direction and distance of the air holes from the center of the nanorods,it is possible to achieve either a single quasi-BIC or three quasi-BICs.The transmission spectra exhibit ultra-narrow lines,and the quasi-BICs demonstrate ultra-high Q factors.Additionally,efficient third-harmonic generation occurs at low pump intensities.The results indicate that the proposed nanostructures of two types of BICs with a flexible modulation hold great potential applications for nonlinear photonic devices.展开更多
We derive the analytical expression of microcavity-enhanced factor for third harmonic generation in terms of detunings, linewidths, and the Purcell factors of the relevant microcavity modes. It is suitable for microca...We derive the analytical expression of microcavity-enhanced factor for third harmonic generation in terms of detunings, linewidths, and the Purcell factors of the relevant microcavity modes. It is suitable for microcavities with any dimensions and arbitrary geometric shapes.展开更多
Effect of pulse slippage on resonant third harmonic generation of a short pulse laser in electron-hole plasma in the presence of wiggler magnetic field has been investigated.The group velocity mismatch of the third ha...Effect of pulse slippage on resonant third harmonic generation of a short pulse laser in electron-hole plasma in the presence of wiggler magnetic field has been investigated.The group velocity mismatch of the third harmonic pulse and the fundamental pulse is significant in electron hole plasma.As the third harmonic pulse has higher group velocity than that of fundamental pulse,therefore,it moves faster than the fundamental pulse.It gets slipped out of the domain of fundamental pulse and its amplitude saturates.Phase matching condition is satisfied by applying wiggler magnetic field,which provides additional angular momentum to the third harmonic photon to make the process resonant.Enhancement in the efficiency of third harmonic generation of an intense short pulse laser in electron-hole plasma embedded with a magnetic wiggler is seen.展开更多
Conventional approaches for obtaining the second and third harmonics typically employ several nonlinear crystals to generate them,which is restricted in application due to the complexity of the optical path and the bu...Conventional approaches for obtaining the second and third harmonics typically employ several nonlinear crystals to generate them,which is restricted in application due to the complexity of the optical path and the bulkiness of the device.In this work,we present a comprehensive theoretical and numerical investigation of the simultaneous generation and competition between the second harmonic waves(SHW)and the third harmonic waves(THW)in a single nonlinear crystal.Through analyzing both small-signal and large-signal regimes,we reveal the complex coupling mechanisms between SHW and THW generation processes.Using periodically poled lithium niobate as an example,we demonstrate that the relative conversion efficiencies between SHW and THW can be freely adjusted by controlling the input fundamental wave power.This work provides new insights for designing efficient frequency converters capable of generating both SHW and THW outputs with controllable intensity ratios.展开更多
We present a new optical microscope in which the light transmitted by a sample-scanned transmission confocal microscope is frequency-tripled by SiOx nanocrystallites in lieu of being transmitted by a confocal pinhole....We present a new optical microscope in which the light transmitted by a sample-scanned transmission confocal microscope is frequency-tripled by SiOx nanocrystallites in lieu of being transmitted by a confocal pinhole. This imaging technique offers an increased contrast and a high scattered light rejection. It is demonstrated that the contrast close to the Sparrow resolution limit is enhanced and the sectioning power are increased with respect to the linear confocal detection mode. An experimental implementation is presented and compared with the conventional linear confocal mode.展开更多
The third-harmonic generation(THG)coefficient for a spherical quantum dot system with inversely quadratic Hellmann plus inversely quadratic potential is investigated theoretically,considering the regulation of quantum...The third-harmonic generation(THG)coefficient for a spherical quantum dot system with inversely quadratic Hellmann plus inversely quadratic potential is investigated theoretically,considering the regulation of quantum size,confinement potential depth and the external environment.The numerical simulation results indicate that the THG coefficient can reach the order of 10~(-12)m~2V~(-2),which strongly relies on the tunable factor,with its resonant peak experiencing a redshift or blueshift.Interestingly,the effect of temperature on the THG coefficient in terms of peak location and size is consistent with the quantum dot radius but contrasts with the hydrostatic pressure.Thus,it is crucial to focus on the influence of internal and external parameters on nonlinear optical effects,and to implement the theory in practical experiments and the manufacture of optoelectronic devices.展开更多
A new nonlinear optical third\|harmonic imaging technology in reflected fashion in bio\|tissues by using cascading effect, a process whereby the second\|order effects combine to contribute to a...A new nonlinear optical third\|harmonic imaging technology in reflected fashion in bio\|tissues by using cascading effect, a process whereby the second\|order effects combine to contribute to a third\|order nonlinear process, has been analyzed. The performance of the reflected optical third harmonic imaging enhanced by cascading effect in bio\|tissues is analyzed with the semi\|classical theory. The microscopic understanding of the enhancement of cascaded optical third\|harmonic imaging in reflected manner in bio\|tissues has been discussed.Some i deas for further enhancement is given.展开更多
The third harmonic generation（THG） of a linear cavity Ti：sapphire regenerative amplifier by use of a K3B6O（10）Cl（KBOC） crystal is studied for the first time. Output power up to 5.9 mW is obtained at a central w...The third harmonic generation（THG） of a linear cavity Ti：sapphire regenerative amplifier by use of a K3B6O（10）Cl（KBOC） crystal is studied for the first time. Output power up to 5.9 mW is obtained at a central wavelength of 263 nm,corresponding to a conversion efficiency of 4.5% to the second harmonic power. Our results show a tremendous potential for nonlinear frequency conversion into the deep ultraviolet range with the new crystal and the output laser power can be further improved.展开更多
Graphene has unique properties paving the way for groundbreaking future applications.Its large optical nonlinearity and ease of integration in devices notably makes it an ideal candidate to become a key component for ...Graphene has unique properties paving the way for groundbreaking future applications.Its large optical nonlinearity and ease of integration in devices notably makes it an ideal candidate to become a key component for all-optical switching and frequency conversion applications.In the terahertz(THz)region,various approaches have been independently demonstrated to optimize the nonlinear effects in graphene,addressing a critical limitation arising from the atomically thin interaction length.Here,we demonstrate sample architectures that combine strategies to enhance THz nonlinearities in graphene-based structures.We achieve this by increasing the interaction length through a multilayered design,controlling carrier density with an electrical gate,and modulating the THz field spatial distribution with a metallic metasurface substrate.Our study specifically investigates third harmonic generation(THG)using a table-top high-field THz source.We measure THG enhancement factors exceeding thirty and propose architectures capable of achieving a two-order-of-magnitude increase.These findings underscore the potential of engineered graphene-based structures in advancing THz frequency conversion technologies for signal processing and wireless communication applications.展开更多
Nonlinear metasurfaces and photonic crystals provide a significant way to generate and manipulate nonlinear signals owing to the resonance-and symmetry-based light-matter interactions supported by the artificial struc...Nonlinear metasurfaces and photonic crystals provide a significant way to generate and manipulate nonlinear signals owing to the resonance-and symmetry-based light-matter interactions supported by the artificial structures.However,the nonlinear conversion efficiency is generally limited by the angular dispersion of optical resonances especially in nonparaxial photonics.Here,we propose a metagrating realizing a quasi-bound-state in the continuum in a flat band to dramatically improve the third harmonic generation(THG)efficiency.A superior operating angular range is achieved based on the interlayer and intralayer couplings,which are introduced by breaking the mirror symmetry of the metagrating.We demonstrate the relation of angular dispersion between the nonlinear and linear responses at different incident angles.We also elucidate the mechanism of these offaxis flat-band-based nonlinear conversions through different mode decomposition.Our scheme provides a robust and analytical way for nonparaxial nonlinear generation and paves the way for further applications such as wide-angle nonlinear information transmission and enhanced nonlinear generation under tight focusing.展开更多
The resonant third-harmonic generation of a tion was investigated. Because of self-focusing self-focusing laser in plasma with a density transi- of the fundamental laser pulse, a transverse intensity gradient was crea...The resonant third-harmonic generation of a tion was investigated. Because of self-focusing self-focusing laser in plasma with a density transi- of the fundamental laser pulse, a transverse intensity gradient was created, which generated a plasma wave at the fundamental wave frequency. Phase matching was satisfied by using a Wiggler magnetic field, which provided additional angular too- mentum to the third-harmonic photon to make the process resonant. An enhancement was observed in the resonant third-harmonic generation of an intense short-pulse laser in plasma embedded with a magnetic Wiggler with a density transition. A plasma density ramp played an important role in the self-focusing, enhancing the third-harmonic generation in plasma. We also examined the ef- fect of the Wiggler magnetic field on the pulse slippage of the third-harmonic pulse in plasma. The pulse slippage was due to the group-velocity mismatch between the fundamental and third-harmonic pulses.展开更多
Tunable coherent radiation of wavelength between 92 nm and 122 nm has been produced in molecular gases of N2, CO, H2 and CH4 by resonant and nonresonant third harmonic generation. Factors with respect to the frequency...Tunable coherent radiation of wavelength between 92 nm and 122 nm has been produced in molecular gases of N2, CO, H2 and CH4 by resonant and nonresonant third harmonic generation. Factors with respect to the frequency conversion efficiency, including the line strength of the nonlinear susceptibility, the density of the media and the phase-matching, are discussed. By analyzing the characteristics of the four-wave mixing spectra in molecular gases, some physical parameters and the population of the energy levels are obtained. This indicates that nonlinear optical frequency conversion process provides a useful method to study the structure and spectra of molecules.展开更多
The efficiency of nanoscale nonlinear elements in photonic integrated circuits is hindered by the physical limits to the nonlinear optical response of dielectrics,which cannot be engineered as it is a fundamental mate...The efficiency of nanoscale nonlinear elements in photonic integrated circuits is hindered by the physical limits to the nonlinear optical response of dielectrics,which cannot be engineered as it is a fundamental material property.Here,we experimentally demonstrate that ultrafast optical nonlinearities in doped semiconductors can be engineered and can easily exceed those of conventional undoped dielectrics.The electron response of heavily doped semiconductors acquires in fact a hydrodynamic character that introduces nonlocal effects as well as additional nonlinear sources.Our experimental findings are supported by a comprehensive computational analysis based on the hydrodynamic model.In particular,by studying third-harmonic generation from plasmonic nanoantenna arrays made out of heavily n-doped InGaAs with increasing levels of free-carrier density,we discriminate between hydrodynamic and dielectric nonlinearities.Most importantly,we demonstrate that the maximum nonlinear efficiency as well as its spectral location can be engineered by tuning the doping level.Crucially,the maximum efficiency can be increased by almost two orders of magnitude with respect to the classical dielectric nonlinearity.Having employed the common material platform InGaAs/InP that supports integrated waveguides,our findings pave the way for future exploitation of plasmonic nonlinearities in all-semiconductor photonic integrated circuits.展开更多
We demonstrated that the epsilon-near-zero(ENZ)aluminum-doped zinc oxide(AZO)thin film exhibited ultrafast nonlinear optical response and efficient third-harmonic generation(THG)experimentally.The AZO film showed sub-...We demonstrated that the epsilon-near-zero(ENZ)aluminum-doped zinc oxide(AZO)thin film exhibited ultrafast nonlinear optical response and efficient third-harmonic generation(THG)experimentally.The AZO film showed sub-picosecond response and broadband wavelength-dependent nonlinear absorption and refraction properties.In addition,the AZO thin film can produce efficient THG with an efficiency of 0.63×10^(-6)at the ENZ wavelength.The experimental results revealed the exceptional nonlinear optical behavior in the AZO thin film,and may provide insights for designing all-optical ultrafast optoelectronic devices.展开更多
In this study,a high-energy,temporally shaped picosecond ultraviolet(UV)laser running at 100 Hz is demonstrated,with its pulses boosted to 120 mJ by cascaded regenerative and double-pass amplifiers,resulting in a gain...In this study,a high-energy,temporally shaped picosecond ultraviolet(UV)laser running at 100 Hz is demonstrated,with its pulses boosted to 120 mJ by cascaded regenerative and double-pass amplifiers,resulting in a gain of more than 10^(8).With precise manipulation and optimization,the amplified laser pulses were flat-top in the temporal and spatial domains to maintain high filling factors,which significantly improved the conversion efficiency of the subsequent third harmonic generation(THG).Finally,91 mJ,470 ps pulses were obtained at 355 nm,corresponding to a conversion efficiency as high as 76%,which,as far as we are aware of,is the highest THG efficiency for a high-repetition-rate picosecond laser.In addition,the energy stability of the UV laser is better than 1.07%(root mean square),which makes this laser an attractive source for a variety of fields including laser conditioning and micro-fabrication.展开更多
Principles of molecular self-assembly into giant hierarchical structures of hundreds of micrometers in size are studied in aggregates of meso-tetra(4-sulfonatophenyl)porphine(TPPS_(4)).The aggregates form a central tu...Principles of molecular self-assembly into giant hierarchical structures of hundreds of micrometers in size are studied in aggregates of meso-tetra(4-sulfonatophenyl)porphine(TPPS_(4)).The aggregates form a central tubular core,which is covered with radially protruding filamentous non-branching aggregates.The filaments cluster and orient at varying angles from the core surface and some filaments form bundles.Due to shape resemblance,the structures are termed giant sea urchin(GSU)aggregates.Spectrally resolved fluorescence microscopy reveals J-and H-bands of TPPS_(4)aggregates in both the central core and the filaments.The fluorescence of the core is quenched while filaments exhibit strong fluorescence.Upon drying,the filament fluorescence gets quenched while the core is less affected,showing stronger relative fluorescence.Fluorescencedetected linear dichroism(FDLD)microscopy reveals that absorption dipoles corresponding to J-bands are oriented along the filament axis.The comparison of FDLD with scanning electron microscopy(SEM)reveals the structure of central core comprised of multilayer ribbons,which wind around the core axis forming a tube.Polarimetric second-harmonic generation(SHG)and thirdharmonic generation microscopy exhibits strong signal from the filaments with nonlinear dipoles oriented close to the filament axis,while central core displays very low SHG due to close to centrosymmetric organization.Large chiral nonlinear susceptibility points to helical arrangement of the filaments.The investigation shows that TPPS_(4)molecules form distinct aggregate types,including chiral nanotubes and nanogranular aggregates that associate into the hierarchical GSU structure,prototypical to complex biological structures.The chiral TPPS_(4)aggregates can serve as harmonophores for nonlinear microscopy.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12174228 and 12274271)。
文摘Two types of bound states in continuum(BICs),symmetry-protected and Brillouin zone folding driven,are identified in hollow Si nanorod arrays.By modulating the direction and distance of the air holes from the center of the nanorods,it is possible to achieve either a single quasi-BIC or three quasi-BICs.The transmission spectra exhibit ultra-narrow lines,and the quasi-BICs demonstrate ultra-high Q factors.Additionally,efficient third-harmonic generation occurs at low pump intensities.The results indicate that the proposed nanostructures of two types of BICs with a flexible modulation hold great potential applications for nonlinear photonic devices.
文摘We derive the analytical expression of microcavity-enhanced factor for third harmonic generation in terms of detunings, linewidths, and the Purcell factors of the relevant microcavity modes. It is suitable for microcavities with any dimensions and arbitrary geometric shapes.
基金Supported by a financial grant from CSIR,New Delhi,India,under Project No.03(1438)/18/EMR-II
文摘Effect of pulse slippage on resonant third harmonic generation of a short pulse laser in electron-hole plasma in the presence of wiggler magnetic field has been investigated.The group velocity mismatch of the third harmonic pulse and the fundamental pulse is significant in electron hole plasma.As the third harmonic pulse has higher group velocity than that of fundamental pulse,therefore,it moves faster than the fundamental pulse.It gets slipped out of the domain of fundamental pulse and its amplitude saturates.Phase matching condition is satisfied by applying wiggler magnetic field,which provides additional angular momentum to the third harmonic photon to make the process resonant.Enhancement in the efficiency of third harmonic generation of an intense short pulse laser in electron-hole plasma embedded with a magnetic wiggler is seen.
基金supported by the Science and Technology Project of Guangdong Province,China(Grant No.2020B010190001)the National Natural Science Foundation of China(Grant No.12434016)+1 种基金the National Key Research and Development Program of China(Grant No.2023YFA1406900)the Fund of the National Postdoctoral Researcher Program(Grant No.GZB20240785).
文摘Conventional approaches for obtaining the second and third harmonics typically employ several nonlinear crystals to generate them,which is restricted in application due to the complexity of the optical path and the bulkiness of the device.In this work,we present a comprehensive theoretical and numerical investigation of the simultaneous generation and competition between the second harmonic waves(SHW)and the third harmonic waves(THW)in a single nonlinear crystal.Through analyzing both small-signal and large-signal regimes,we reveal the complex coupling mechanisms between SHW and THW generation processes.Using periodically poled lithium niobate as an example,we demonstrate that the relative conversion efficiencies between SHW and THW can be freely adjusted by controlling the input fundamental wave power.This work provides new insights for designing efficient frequency converters capable of generating both SHW and THW outputs with controllable intensity ratios.
基金The Si0x nanocrystals and clusters were deposited by D. Scuderi, 0. Albert, A. Dos Santos and J. Etchepare at the L0A. We thank Bertrand Reynier, Unité de Mécanique, ENSTA, France, for sample characterization by electron microscopy.
文摘We present a new optical microscope in which the light transmitted by a sample-scanned transmission confocal microscope is frequency-tripled by SiOx nanocrystallites in lieu of being transmitted by a confocal pinhole. This imaging technique offers an increased contrast and a high scattered light rejection. It is demonstrated that the contrast close to the Sparrow resolution limit is enhanced and the sectioning power are increased with respect to the linear confocal detection mode. An experimental implementation is presented and compared with the conventional linear confocal mode.
基金National Natural Science Foundation of China(Grant Nos.11674312,52174161,51702003,12174161 and 61775087)Anhui University of Science and Technology(Grant No.2023CX2141)。
文摘The third-harmonic generation(THG)coefficient for a spherical quantum dot system with inversely quadratic Hellmann plus inversely quadratic potential is investigated theoretically,considering the regulation of quantum size,confinement potential depth and the external environment.The numerical simulation results indicate that the THG coefficient can reach the order of 10~(-12)m~2V~(-2),which strongly relies on the tunable factor,with its resonant peak experiencing a redshift or blueshift.Interestingly,the effect of temperature on the THG coefficient in terms of peak location and size is consistent with the quantum dot radius but contrasts with the hydrostatic pressure.Thus,it is crucial to focus on the influence of internal and external parameters on nonlinear optical effects,and to implement the theory in practical experiments and the manufacture of optoelectronic devices.
文摘A new nonlinear optical third\|harmonic imaging technology in reflected fashion in bio\|tissues by using cascading effect, a process whereby the second\|order effects combine to contribute to a third\|order nonlinear process, has been analyzed. The performance of the reflected optical third harmonic imaging enhanced by cascading effect in bio\|tissues is analyzed with the semi\|classical theory. The microscopic understanding of the enhancement of cascaded optical third\|harmonic imaging in reflected manner in bio\|tissues has been discussed.Some i deas for further enhancement is given.
基金supported by the National Key Basic Research Program of China(Grant No.2013CB922402)the Key Program of the National Natural Science Foundation of China(Grant Nos.11434016 and 61575219)the International Joint Research Program of the National Natural Science Foundation of China(Grant No.61210017)
文摘The third harmonic generation（THG） of a linear cavity Ti：sapphire regenerative amplifier by use of a K3B6O（10）Cl（KBOC） crystal is studied for the first time. Output power up to 5.9 mW is obtained at a central wavelength of 263 nm,corresponding to a conversion efficiency of 4.5% to the second harmonic power. Our results show a tremendous potential for nonlinear frequency conversion into the deep ultraviolet range with the new crystal and the output laser power can be further improved.
基金funding from the Natural Sciences and Engineering Research Council of Canada(NSERC)Discovery funding program(RGPIN-2023-05365)the University of Bayreuth Centre of International Excellence"Alexander von Humboldt".G.H.acknowledges funding by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation),via project 492723217.A.Maleki,G.Herink and J.-M.Menard acknowledge financial support from the Mitacs Globalink Research Award.
文摘Graphene has unique properties paving the way for groundbreaking future applications.Its large optical nonlinearity and ease of integration in devices notably makes it an ideal candidate to become a key component for all-optical switching and frequency conversion applications.In the terahertz(THz)region,various approaches have been independently demonstrated to optimize the nonlinear effects in graphene,addressing a critical limitation arising from the atomically thin interaction length.Here,we demonstrate sample architectures that combine strategies to enhance THz nonlinearities in graphene-based structures.We achieve this by increasing the interaction length through a multilayered design,controlling carrier density with an electrical gate,and modulating the THz field spatial distribution with a metallic metasurface substrate.Our study specifically investigates third harmonic generation(THG)using a table-top high-field THz source.We measure THG enhancement factors exceeding thirty and propose architectures capable of achieving a two-order-of-magnitude increase.These findings underscore the potential of engineered graphene-based structures in advancing THz frequency conversion technologies for signal processing and wireless communication applications.
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFA1400601,and 2022YFA1404501)the National Natural Science Fund for Distinguished Young Scholar(Grant No.11925403)the National Natural Science Foundation of China(Grant Nos.12122406,12192253,12274239,12274237,and U22A20258)。
文摘Nonlinear metasurfaces and photonic crystals provide a significant way to generate and manipulate nonlinear signals owing to the resonance-and symmetry-based light-matter interactions supported by the artificial structures.However,the nonlinear conversion efficiency is generally limited by the angular dispersion of optical resonances especially in nonparaxial photonics.Here,we propose a metagrating realizing a quasi-bound-state in the continuum in a flat band to dramatically improve the third harmonic generation(THG)efficiency.A superior operating angular range is achieved based on the interlayer and intralayer couplings,which are introduced by breaking the mirror symmetry of the metagrating.We demonstrate the relation of angular dispersion between the nonlinear and linear responses at different incident angles.We also elucidate the mechanism of these offaxis flat-band-based nonlinear conversions through different mode decomposition.Our scheme provides a robust and analytical way for nonparaxial nonlinear generation and paves the way for further applications such as wide-angle nonlinear information transmission and enhanced nonlinear generation under tight focusing.
文摘The resonant third-harmonic generation of a tion was investigated. Because of self-focusing self-focusing laser in plasma with a density transi- of the fundamental laser pulse, a transverse intensity gradient was created, which generated a plasma wave at the fundamental wave frequency. Phase matching was satisfied by using a Wiggler magnetic field, which provided additional angular too- mentum to the third-harmonic photon to make the process resonant. An enhancement was observed in the resonant third-harmonic generation of an intense short-pulse laser in plasma embedded with a magnetic Wiggler with a density transition. A plasma density ramp played an important role in the self-focusing, enhancing the third-harmonic generation in plasma. We also examined the ef- fect of the Wiggler magnetic field on the pulse slippage of the third-harmonic pulse in plasma. The pulse slippage was due to the group-velocity mismatch between the fundamental and third-harmonic pulses.
文摘Tunable coherent radiation of wavelength between 92 nm and 122 nm has been produced in molecular gases of N2, CO, H2 and CH4 by resonant and nonresonant third harmonic generation. Factors with respect to the frequency conversion efficiency, including the line strength of the nonlinear susceptibility, the density of the media and the phase-matching, are discussed. By analyzing the characteristics of the four-wave mixing spectra in molecular gases, some physical parameters and the population of the energy levels are obtained. This indicates that nonlinear optical frequency conversion process provides a useful method to study the structure and spectra of molecules.
文摘The efficiency of nanoscale nonlinear elements in photonic integrated circuits is hindered by the physical limits to the nonlinear optical response of dielectrics,which cannot be engineered as it is a fundamental material property.Here,we experimentally demonstrate that ultrafast optical nonlinearities in doped semiconductors can be engineered and can easily exceed those of conventional undoped dielectrics.The electron response of heavily doped semiconductors acquires in fact a hydrodynamic character that introduces nonlocal effects as well as additional nonlinear sources.Our experimental findings are supported by a comprehensive computational analysis based on the hydrodynamic model.In particular,by studying third-harmonic generation from plasmonic nanoantenna arrays made out of heavily n-doped InGaAs with increasing levels of free-carrier density,we discriminate between hydrodynamic and dielectric nonlinearities.Most importantly,we demonstrate that the maximum nonlinear efficiency as well as its spectral location can be engineered by tuning the doping level.Crucially,the maximum efficiency can be increased by almost two orders of magnitude with respect to the classical dielectric nonlinearity.Having employed the common material platform InGaAs/InP that supports integrated waveguides,our findings pave the way for future exploitation of plasmonic nonlinearities in all-semiconductor photonic integrated circuits.
基金supported by the National Natural Science Foundation of China(No.61975055)the Natural Science Foundation of Hunan Province(No.2023JJ30165)。
文摘We demonstrated that the epsilon-near-zero(ENZ)aluminum-doped zinc oxide(AZO)thin film exhibited ultrafast nonlinear optical response and efficient third-harmonic generation(THG)experimentally.The AZO film showed sub-picosecond response and broadband wavelength-dependent nonlinear absorption and refraction properties.In addition,the AZO thin film can produce efficient THG with an efficiency of 0.63×10^(-6)at the ENZ wavelength.The experimental results revealed the exceptional nonlinear optical behavior in the AZO thin film,and may provide insights for designing all-optical ultrafast optoelectronic devices.
基金supported by the National Natural Science Foundation of China(61925507 and 62075227)National Key R&D Program of China(2017YFE0123700)+3 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(XDB1603)Program of Shanghai Academic/Technology Research Leader(18XD1404200)Shanghai Municipal Science and Technology Major Project(2017SHZDZX02)Youth Innovation Promotion Association CAS(2020248)。
文摘In this study,a high-energy,temporally shaped picosecond ultraviolet(UV)laser running at 100 Hz is demonstrated,with its pulses boosted to 120 mJ by cascaded regenerative and double-pass amplifiers,resulting in a gain of more than 10^(8).With precise manipulation and optimization,the amplified laser pulses were flat-top in the temporal and spatial domains to maintain high filling factors,which significantly improved the conversion efficiency of the subsequent third harmonic generation(THG).Finally,91 mJ,470 ps pulses were obtained at 355 nm,corresponding to a conversion efficiency as high as 76%,which,as far as we are aware of,is the highest THG efficiency for a high-repetition-rate picosecond laser.In addition,the energy stability of the UV laser is better than 1.07%(root mean square),which makes this laser an attractive source for a variety of fields including laser conditioning and micro-fabrication.
基金supported by European Regional Development Fund(No.01.2.2.-LMT-K-718-02-0016)under grant agreement with the Research Council of Lithuania(LMTLT)Support was also provided by the Natural Sciences and Engineering Research Council of Canada(NSERC)(Nos.RGPIN-2017-06923 and DGDND-2017-00099)+1 种基金I.D.was supported by GINOP-2.3.2-15-2016-00058 and G.S.by GINOP-2.3.2-15-2016-00001ELKH KÜ-37/2020 grants from the Hungarian Ministry for National Economy and the Eötvös Loránd Research Network,respectively。
文摘Principles of molecular self-assembly into giant hierarchical structures of hundreds of micrometers in size are studied in aggregates of meso-tetra(4-sulfonatophenyl)porphine(TPPS_(4)).The aggregates form a central tubular core,which is covered with radially protruding filamentous non-branching aggregates.The filaments cluster and orient at varying angles from the core surface and some filaments form bundles.Due to shape resemblance,the structures are termed giant sea urchin(GSU)aggregates.Spectrally resolved fluorescence microscopy reveals J-and H-bands of TPPS_(4)aggregates in both the central core and the filaments.The fluorescence of the core is quenched while filaments exhibit strong fluorescence.Upon drying,the filament fluorescence gets quenched while the core is less affected,showing stronger relative fluorescence.Fluorescencedetected linear dichroism(FDLD)microscopy reveals that absorption dipoles corresponding to J-bands are oriented along the filament axis.The comparison of FDLD with scanning electron microscopy(SEM)reveals the structure of central core comprised of multilayer ribbons,which wind around the core axis forming a tube.Polarimetric second-harmonic generation(SHG)and thirdharmonic generation microscopy exhibits strong signal from the filaments with nonlinear dipoles oriented close to the filament axis,while central core displays very low SHG due to close to centrosymmetric organization.Large chiral nonlinear susceptibility points to helical arrangement of the filaments.The investigation shows that TPPS_(4)molecules form distinct aggregate types,including chiral nanotubes and nanogranular aggregates that associate into the hierarchical GSU structure,prototypical to complex biological structures.The chiral TPPS_(4)aggregates can serve as harmonophores for nonlinear microscopy.
