Nonlinear silicon photonics has shown an ability to generate, compact chip at a potential low cost. There are still barriers limitations. In this review, hybrid structures with some manipulate, and detect optical sign...Nonlinear silicon photonics has shown an ability to generate, compact chip at a potential low cost. There are still barriers limitations. In this review, hybrid structures with some manipulate, and detect optical signals on an ultrahindering its development due to essential material specific materials developed for nonlinear silicon photonics are discussed. The combination of silicon and the nonlinear materials takes advantage of both materials, which shows great potential to improve the performance and expand the applications for nonlinear silicon photonics.展开更多
The generation of optical vortices from nonlinear photonic crystals(NPCs)with spatially modulated second-order nonlinearity offers a promising approach to extend the working wavelength and topological charge of vortex...The generation of optical vortices from nonlinear photonic crystals(NPCs)with spatially modulated second-order nonlinearity offers a promising approach to extend the working wavelength and topological charge of vortex beams for various applications.In this work,the second harmonic(SH)optical vortex beams generated from nonlinear fork gratings under Gaussian beam illumination are numerically investigated.The far-field intensity and phase distributions,as well as the orbital angular momentum(OAM)spectra of the SH beams,are analyzed for different structural topological charges and diffraction orders.Results reveal that higher-order diffraction and larger structural topological charges lead to angular interference patterns and non-uniform intensity distributions,deviating from the standard vortex profile.To optimize the SH vortex quality,the effects of the fundamental wave beam waist,crystal thickness,and grating duty cycle are explored.It is shown that increasing the beam waist can effectively suppress diffraction order interference and improve the beam’s quality.This study provides theoretical guidance for enhancing the performance of nonlinear optical devices based on NPCs.展开更多
The electron movement based on the multi-photon nonlinear Compton scattering with the extra-intense stationary laser field is discussed by using KMR (Kroll-Morton-Rosenbluth) theory.We find that there exists only an e...The electron movement based on the multi-photon nonlinear Compton scattering with the extra-intense stationary laser field is discussed by using KMR (Kroll-Morton-Rosenbluth) theory.We find that there exists only an evolution from periodicity to non-periodicity of the un-captured electron phase orbits after the energy exchange between the electron beam and laser fields.With the increase of the absorbed photon number n by an electron, this evolution will be more and more faster, while it is rapidly decreased with the enhancement of the collision non-flexibility ξ of the electrons and photons; When the electrons are captured by the laser fields, the evolution is finished, the electrons will stably transport,and the photons dont give up the energy to these electrons.展开更多
Hyperentanglement is a promising resource for achieving high capacity quantum communication.Here,we propose a compact scheme for the generation of path-frequency hyperentangled photon pairs via spontaneous parametric ...Hyperentanglement is a promising resource for achieving high capacity quantum communication.Here,we propose a compact scheme for the generation of path-frequency hyperentangled photon pairs via spontaneous parametric down-conversion(SPDC)processes,where six different paths and two different frequencies are covered.A two-dimensional periodicalχ^((2))nonlinear photonic crystal(NPC)is designed to satisfy type-Ⅰquasi-phase-matching conditions in the plane perpendicular to the incident pump beam,and a perfect phase match is achieved along the pump beam's direction to ensure high conversion efficiency,with theoretically estimated photon flux up to 2.068×10^(5) pairs·s^(-1)·mm^(-2).We theoretically calculate the joint-spectral amplitude(JSA)of the generated photon pair and perform Schmidt decomposition on it,where the resulting entropy S of entanglement and effective Schmidt rank K reach 3.2789 and 6.4675,respectively.Our hyperentangled photon source scheme could provide new avenues for high-dimensional quantum communication and high-speed quantum information processing.展开更多
Ultrafast lasers play an important role in a variety of applications ranging from optical communications to medical diagnostics and industrial materials processing. Graphene and other two-dimensional（2D） noncarbon m...Ultrafast lasers play an important role in a variety of applications ranging from optical communications to medical diagnostics and industrial materials processing. Graphene and other two-dimensional（2D） noncarbon materials, including topological insulators（TIs）, transition metal dichalcogenides（TMDCs）, phosphorene, bismuthene, and antimonene, have witnessed a very fast development of both fundamental and practical aspects in ultrafast photonics since 2009. Their unique nonlinear optical properties enable them to be used as excellent saturable absorbers（SAs） that have fast responses and broadband operation, and can be easily integrated into lasers. Here, we catalog and review recent progress in the exploitation of these 2D noncarbon materials in this emerging field. The fabrication techniques, nonlinear optical properties, and device integration strategies of 2D noncarbon materials are first introduced with a comprehensive view. Then, various mode-locked/Q-switched lasers（e.g., fiber, solid-state, disk, and waveguide lasers） based on 2D noncarbon materials are reviewed. In addition, versatile soliton pulses generated from the mode-locked fiber lasers based on 2D noncarbon materials are also summarized. Finally, future challenges and perspectives of 2D materials-based lasers are addressed.展开更多
Generation of hyperentangled photon pairs is investigated based on the lithium niobate straight waveguide.We propose to use the nonlinear optical process of spontaneous parametric down-conversion(SPDC)and a well-desig...Generation of hyperentangled photon pairs is investigated based on the lithium niobate straight waveguide.We propose to use the nonlinear optical process of spontaneous parametric down-conversion(SPDC)and a well-designed lithium niobate waveguide structure to generate a hyperentangled(in the polarization dimension and the energy-time dimension)two-photon state.By performing numerical simulations of the waveguide structure and calculating the possible polarization states,joint spectral amplitudes(JSA),and joint temporal amplitudes(JTA)of the generated photon pair,we show that the generated photon pair is indeed hyperentangled in both the polarization dimension and the energy-time dimension.展开更多
The field of nonlinear photonics is in full development. This special issue of Photonics Research takes you through the current issues of this fast-growing field of research, drawing on the current state of the art an...The field of nonlinear photonics is in full development. This special issue of Photonics Research takes you through the current issues of this fast-growing field of research, drawing on the current state of the art and seeking, through a selection of articles, to outline some trends for the future.展开更多
In the domain of spectroscopy,miniaturization efforts often face significant challenges,particularly in achieving high spectral resolution and precise construction.Here,we introduce a computational spectrometer powere...In the domain of spectroscopy,miniaturization efforts often face significant challenges,particularly in achieving high spectral resolution and precise construction.Here,we introduce a computational spectrometer powered by a nonlinear photonic memristor with a WSe2 homojunction.This approach overcomes traditional limitations,such as constrained Fermi level tunability,persistent dark current,and limited photoresponse dimensionality through dynamic energy band modulation driven by palladium(Pd)ion migration.The critical role of Pd ion migration is thoroughly supported by first-principles calculations,numerical simulations,and experimental verification,demonstrating its effectiveness in enhancing device performance.Additionally,we integrate this dynamic modulation with a specialized nonlinear neural network tailored to address the memristor's inherent nonlinear photoresponse.This combination enables our spectrometer to achieve an exceptional peak wavelength accuracy of o.18 nm and a spectral resolution of 2 nm within the 630-640 nm range.This development marks a significant advancement in the creation of compact,high-effciency spectroscopic instruments and offers a versatile platform for applications across diverse material systems.展开更多
It is commonly assumed that nonlinear frequency conversion requires lasers with high coherence;however,this assumption has constrained our broader understanding of coherence and overlooked the potential role of incohe...It is commonly assumed that nonlinear frequency conversion requires lasers with high coherence;however,this assumption has constrained our broader understanding of coherence and overlooked the potential role of incoherence in nonlinear interactions.In this work,we study the synthesis of optical spatial coherence in second harmonic generation using quadratic nonlinear photonic crystals.We demonstrate a method where the second harmonic coherence is customized by employing quantitative phase retrieval and a complex square-root filter sequentially on fundamental frequency speckles.As a proof-of-concept,we experimentally show incoherent imaging of a smiley face transitioning from infrared to visible light.Moreover,we apply this method to produce two representative types of structured light beams in second harmonic generation:incoherent vortex and Airy beams.During the nonlinear synthesis of incoherent vortex beams,we have,for the first time,experimentally verified the conservation of orbital angular momentum in the nonlinear frequency conversion process of a low-coherence source.Furthermore,the generated second-harmonic incoherent Airy beam preserves the self-acceleration characteristics of its fundamental frequency counterpart,remaining unaffected by reductions in coherence.Our results not only deepen the fundamental understanding of optical coherence but also unlock exciting possibilities for applications in infrared imaging and fluorescence microscopy where optical nonlinear interactions play an important role.展开更多
We fabricated a three-dimensional nonlinear photonic crystal in a Sr_(0.61)Ba_(0.39)Nb_2O_6(SBN)crystal using femtosecond laser direct writing of ferroelectric domain structures.The crystal features three layers of fo...We fabricated a three-dimensional nonlinear photonic crystal in a Sr_(0.61)Ba_(0.39)Nb_2O_6(SBN)crystal using femtosecond laser direct writing of ferroelectric domain structures.The crystal features three layers of fork-shaped gratings,each oriented differently.These gratings convert an incident vortex beam into a second-harmonic Gaussian beam in specific directions.By altering the vortex beam's topological charge,we can control the emission direction of the second-harmonic Gaussian beam,enabling flexible all-optical switching and manipulation.This work provides a foundation for controlling photon angular momentum in nonlinear optical frequency-conversion processes.展开更多
Nonlinear photonic crystals[NPCs]with modulated second-order nonlinear coefficients[χ^([2])]enable quasi-phase-matching[QPM]for efficient frequency conversion.Traditional electric-field poling is limited to two-dimen...Nonlinear photonic crystals[NPCs]with modulated second-order nonlinear coefficients[χ^([2])]enable quasi-phase-matching[QPM]for efficient frequency conversion.Traditional electric-field poling is limited to two-dimensional domain engineering and cannot achieve three-dimensional[3D]χ^([2])distributions,while femtosecond laser writing[FLW]offers greater control but introduces crystal damage.In this work,we use the pyroelectric-based fabrication process by performing the cooling step in a vacuum after FLW,suppressing thermal fluctuations,and maximizing the pyroelectric field.Vacuum cooling significantly improves domain inversion probability and uniformity compared to air cooling,making the periodicity close to electrical poling.Real-time polarized microscopy reveals improved domain growth,while nonlinear diffraction analysis confirms negligible refractive index changes.We demonstrate domain-inverted NPCs with a periodicity of 4μm,achieving QPM at near-infrared wavelengths.This method provides a scalable and efficient pathway for advanced nonlinear photonic devices.展开更多
Chip-scale integration of optical frequency combs,particularly soliton microcombs,enables miniaturized instrumentation for timekeeping,ranging,and spectroscopy.Although soliton microcombs have been demonstrated on var...Chip-scale integration of optical frequency combs,particularly soliton microcombs,enables miniaturized instrumentation for timekeeping,ranging,and spectroscopy.Although soliton microcombs have been demonstrated on various material platforms,realizing complete comb functionality on photonic chips requires the co-integration of highspeed modulators and efficient frequency doublers,features that are available in a monolithic form on X-cut thin-film lithium niobate(TFLN).However,the pronounced Raman nonlinearity associated with extraordinary light in this platform has so far precluded soliton microcomb generation.Here,we report the generation of transverse-electric-polarized soliton microcombs with a 25 GHz repetition rate in high-Q microresonators on X-cut TFLN chips.By precisely orienting the racetrack microresonator relative to the optical axis,we mitigate Raman nonlinearity and enable soliton formation under continuous-wave laser pumping.Moreover,the soliton microcomb spectra are extended to 350 nm with pulsed laser pumping.This work expands the capabilities of TFLN photonics and paves the way for the monolithic integration of fast-tunable,self-referenced microcombs.展开更多
Two-dimensional（2D） materials have emerged as attractive mediums for fabricating versatile optoelectronic devices. Recently, few-layer molybdenum disulfide（MoS2）, as a shining 2D material, has been discovered to p...Two-dimensional（2D） materials have emerged as attractive mediums for fabricating versatile optoelectronic devices. Recently, few-layer molybdenum disulfide（MoS2）, as a shining 2D material, has been discovered to possess both the saturable absorption effect and large nonlinear refractive index. Herein, taking advantage of the unique nonlinear optical properties of MoS2, we fabricated a highly nonlinear saturable absorption photonic device by depositing the few-layer MoS2 onto the microfiber. With the proposed MoS2 photonic device, apart from the conventional soliton patterns, the mode-locked pulses could be shaped into some new soliton patterns, namely,multiple soliton molecules, localized chaotic multipulses, and double-scale soliton clusters. Our findings indicate that the few-layer MoS2-deposited microfiber could operate as a promising highlynonlinear photonic device for the related nonlinear optics applications.展开更多
The nonlinear optical （NLO） and optical limiting （OL） properties of three new structures of organic NLO vip host Poly（N-vinylcarbozole）/disperse orange 3 （PVK/DO3）, PVK/disperse orange 13 （PVK/DO13）. and P...The nonlinear optical （NLO） and optical limiting （OL） properties of three new structures of organic NLO vip host Poly（N-vinylcarbozole）/disperse orange 3 （PVK/DO3）, PVK/disperse orange 13 （PVK/DO13）. and PVK/disperse orange 25 （PVK/DO25） as a solution at different concentrations and as a thin-film sample are studied using continuous wave z-scan system at 532 nm. The open-aperture z-scan data of the NLO materials in the solution and thin-film samples displayed two-photon and saturable absorptions, respectively. The PVK/DO13 exhibites the largest and best values of the nonlinearities, such as n2, β, X（3） compared with those of PVK/DO3 and PVK/DO25. This nonlinearity increases as the concentration increases. Tile results indicate that these NLO materials are good candidates for optical switching and OL devices.展开更多
The nonlinear Talbot effect is a near-field nonlinear diffraction phenomenon in which the self-imaging of periodic objects is formed by the second harmonics of the incident laser beam. We demonstrate the first, to the...The nonlinear Talbot effect is a near-field nonlinear diffraction phenomenon in which the self-imaging of periodic objects is formed by the second harmonics of the incident laser beam. We demonstrate the first, to the best of our knowledge, example of nonlinear Talbot self-healing, i.e., the capability of creating defect-free images from faulty nonlinear optical structures. In particular, we employ the tightly focused femtosecond infrared optical pulses to fabricate LiNbO_(3) nonlinear photonic crystals and show that the defects in the form of the missing points of two-dimensional square and hexagonal periodic structures are restored in the second harmonic images at the first nonlinear Talbot plane. The observed nonlinear Talbot self-healing opens up new possibilities for defect-tolerant optical lithography and printing.展开更多
The design of nonlinear photonic Vogel's spiral based on quasi-crystal theory was demonstrated.Two main parameters of Vogel's spiral were arranged to obtain multi-reciprocal circles.Typical structure was fabri...The design of nonlinear photonic Vogel's spiral based on quasi-crystal theory was demonstrated.Two main parameters of Vogel's spiral were arranged to obtain multi-reciprocal circles.Typical structure was fabricated by the near-infrared femtosecond laser poling technique,forming a nonlinear photonic structure,and multiple ring-like nonlinear Raman±Nath second-harmonic generation processes were realized and analyzed in detail.The structure for the cascaded thirdharmonic generation process was predicted.The results could help deepen the understanding of Vogel's spiral and quasi-crystal and pave the way for the combination of quasi-crystal theory with more aperiodic structures.展开更多
A 3D nonlinear photonic crystal containing four parallel segments of periodicχ^((2))grating structure is fabricated employing the femtosecond laser poling of ferroelectric Ca_(0.28)Ba_(0.72)Nb_(2)O_(6) crystal.The se...A 3D nonlinear photonic crystal containing four parallel segments of periodicχ^((2))grating structure is fabricated employing the femtosecond laser poling of ferroelectric Ca_(0.28)Ba_(0.72)Nb_(2)O_(6) crystal.The second harmonic generation from this foursegment structure is studied with a fundamental Gaussian wave.By tuning the wavelength of the fundamental wave,the second harmonic varies from the Laguerre-Gaussian beam(topological charge l_(c)=1)to the higher-order Hermite-Gaussian beam and Laguerre-Gaussian again(l_(c)=−1).This effect is caused by the wavelength-dependent phase delays introduced by the four-grating structure.Our study contributes to a deeper understanding of nonlinear wave interactions in 3D nonlinear photonic crystals.It also offers new possibilities for special beam generation at new frequencies and their control.展开更多
We investigate in this paper the influence of slow light on the balance between the Kerr and two-photon absorption(TPA) processes in silicon slotted hybrid nonlinear waveguides. Three typical silicon photonic waveguid...We investigate in this paper the influence of slow light on the balance between the Kerr and two-photon absorption(TPA) processes in silicon slotted hybrid nonlinear waveguides. Three typical silicon photonic waveguide geometries are studied to estimate the influence of the light slow-down factor on the mode field overlap with the silicon region, as well as on the complex effective nonlinear susceptibility. It is found that slotted photonic crystal modes tend to focalize in their hollow core with increasing group index(n_G) values. Considering a hybrid integration of nonlinear polymers in such slotted waveguides, a relative decrease of the TPA process by more factor of 2 is predicted from n_G=10 to n_G=50. As a whole, this work shows that the relative influence of TPA decreases for slotted waveguides operating in the slow light regime, making them a suitable platform for third-order nonlinear optics.展开更多
Submicron-thick thin-film lithium niobate(TFLN)has emerged as a promising platform for nonlinear integrated photonics.In this work,we demonstrate the efficient simultaneous generation of broadband 2nd–8th harmonics i...Submicron-thick thin-film lithium niobate(TFLN)has emerged as a promising platform for nonlinear integrated photonics.In this work,we demonstrate the efficient simultaneous generation of broadband 2nd–8th harmonics in chirped periodically poled(CPP)TFLN.This is achieved through the synergistic effects of cascadedχ^((2))nonlinear up-conversion andχ^((3))self-phase modulation,driven by near-infrared femtosecond pulses with a central wavelength of 2100 nm and a pulse energy of 1.2μJ.Remarkably,the 7th and 8th harmonics extend into the deep ultraviolet(DUV)region,reaching wavelengths as short as 250 nm.The 3rd–8th harmonic spectra seamlessly connect,forming a broadband supercontinuum spanning from the DUV to the visible range(250–800 nm,-25 d B),with an on-chip conversion efficiency of 19%(0.23μJ).This achievement is attributed to the CPP-TFLN providing multiple broadband reciprocal lattice vector bands,enabling quasi-phase matching for a series ofχ^((2))nonlinear processes,including second harmonic generation(SHG),cascaded SHG,and third harmonic generation.Furthermore,we demonstrated the significant role of cascadedχ^((2))phase-mismatched nonlinear processes in high-harmonic generation(HHG).Our work unveils the intricate and diverse nonlinear optical interactions in TFLN,offering a clear path toward efficient on-chip HHG and compact coherent white-light sources extending into the DUV.展开更多
In this paper,we have proposed and demonstrated the generation of passively mode-locked pulses and dissipative soliton resonance in an erbium-doped fiber laser based on Fe3O4 nanoparticles as saturable absorbers.We ob...In this paper,we have proposed and demonstrated the generation of passively mode-locked pulses and dissipative soliton resonance in an erbium-doped fiber laser based on Fe3O4 nanoparticles as saturable absorbers.We obtained self-starting mode-locked pulses with fundamental repetition frequency of 7.69 MHz and center wavelength of 1561 nm.The output of a pulsed laser has spectral width of 0.69 nm and pulse duration of 14 ns with rectangular pulse profile at the pump power of 190 mW.As far as we know,this is the first time that Fe3O4 nanoparticles have been developed as low-dimensional materials for passive mode-locking with rectangular pulse.Our experiments have confirmed that Fe3O4 has a wide prospect as a nonlinear photonics device for ultrafast fiber laser applications.展开更多
基金National Natural Science Foundation of China(NSFC)(11374263,61422510,61431166001,61725503)Natural Science Foundation of Zhejiang Province(Z18F050002)National Major Research and Development Program(2016YFB0402502)
文摘Nonlinear silicon photonics has shown an ability to generate, compact chip at a potential low cost. There are still barriers limitations. In this review, hybrid structures with some manipulate, and detect optical signals on an ultrahindering its development due to essential material specific materials developed for nonlinear silicon photonics are discussed. The combination of silicon and the nonlinear materials takes advantage of both materials, which shows great potential to improve the performance and expand the applications for nonlinear silicon photonics.
基金supported by the National Nat-ural Science Foundation of China(Nos.12192251,12174185,92163216,and 62288101).
文摘The generation of optical vortices from nonlinear photonic crystals(NPCs)with spatially modulated second-order nonlinearity offers a promising approach to extend the working wavelength and topological charge of vortex beams for various applications.In this work,the second harmonic(SH)optical vortex beams generated from nonlinear fork gratings under Gaussian beam illumination are numerically investigated.The far-field intensity and phase distributions,as well as the orbital angular momentum(OAM)spectra of the SH beams,are analyzed for different structural topological charges and diffraction orders.Results reveal that higher-order diffraction and larger structural topological charges lead to angular interference patterns and non-uniform intensity distributions,deviating from the standard vortex profile.To optimize the SH vortex quality,the effects of the fundamental wave beam waist,crystal thickness,and grating duty cycle are explored.It is shown that increasing the beam waist can effectively suppress diffraction order interference and improve the beam’s quality.This study provides theoretical guidance for enhancing the performance of nonlinear optical devices based on NPCs.
文摘The electron movement based on the multi-photon nonlinear Compton scattering with the extra-intense stationary laser field is discussed by using KMR (Kroll-Morton-Rosenbluth) theory.We find that there exists only an evolution from periodicity to non-periodicity of the un-captured electron phase orbits after the energy exchange between the electron beam and laser fields.With the increase of the absorbed photon number n by an electron, this evolution will be more and more faster, while it is rapidly decreased with the enhancement of the collision non-flexibility ξ of the electrons and photons; When the electrons are captured by the laser fields, the evolution is finished, the electrons will stably transport,and the photons dont give up the energy to these electrons.
基金Project supported by the Key-Area Research and Development Program of Guangdong Province of China (Grant No.2018B030325002)the National Natural Science Foundation of China (Grant No.62075129)+2 种基金the Open Project Program of SJTU-Pinghu Institute of Intelligent Optoelectronics (Grant No.2022SPIOE204)the Science and Technology on Metrology and Calibration Laboratory (Grant No.JLJK2022001B002)the Sichuan Provincial Key Laboratory of Microwave Photonics (Grant No.2023-04)。
文摘Hyperentanglement is a promising resource for achieving high capacity quantum communication.Here,we propose a compact scheme for the generation of path-frequency hyperentangled photon pairs via spontaneous parametric down-conversion(SPDC)processes,where six different paths and two different frequencies are covered.A two-dimensional periodicalχ^((2))nonlinear photonic crystal(NPC)is designed to satisfy type-Ⅰquasi-phase-matching conditions in the plane perpendicular to the incident pump beam,and a perfect phase match is achieved along the pump beam's direction to ensure high conversion efficiency,with theoretically estimated photon flux up to 2.068×10^(5) pairs·s^(-1)·mm^(-2).We theoretically calculate the joint-spectral amplitude(JSA)of the generated photon pair and perform Schmidt decomposition on it,where the resulting entropy S of entanglement and effective Schmidt rank K reach 3.2789 and 6.4675,respectively.Our hyperentangled photon source scheme could provide new avenues for high-dimensional quantum communication and high-speed quantum information processing.
基金supported by the Program for Equipment Pre-research Field Funds(No.6140414040116CB01012)the National Natural Science Foundation of China(Nos.61575051 and 11704086)the 111 project of the Harbin Engineering University(No.B13015)
文摘Ultrafast lasers play an important role in a variety of applications ranging from optical communications to medical diagnostics and industrial materials processing. Graphene and other two-dimensional（2D） noncarbon materials, including topological insulators（TIs）, transition metal dichalcogenides（TMDCs）, phosphorene, bismuthene, and antimonene, have witnessed a very fast development of both fundamental and practical aspects in ultrafast photonics since 2009. Their unique nonlinear optical properties enable them to be used as excellent saturable absorbers（SAs） that have fast responses and broadband operation, and can be easily integrated into lasers. Here, we catalog and review recent progress in the exploitation of these 2D noncarbon materials in this emerging field. The fabrication techniques, nonlinear optical properties, and device integration strategies of 2D noncarbon materials are first introduced with a comprehensive view. Then, various mode-locked/Q-switched lasers（e.g., fiber, solid-state, disk, and waveguide lasers） based on 2D noncarbon materials are reviewed. In addition, versatile soliton pulses generated from the mode-locked fiber lasers based on 2D noncarbon materials are also summarized. Finally, future challenges and perspectives of 2D materials-based lasers are addressed.
基金the Key-Area Research and Development Program of Guangdong Province of China(Grant No.2018B030325002)the National Natural Science Foundation of China(Grant No.62075129)+1 种基金the Open Project Program of SJTU-Pinghu Institute of Intelligent Optoelectronics(Grant No.2022SPIOE204)the Science and Technology on Metrology and Calibration Laboratory(Grant No.JLJK2022001B002)。
文摘Generation of hyperentangled photon pairs is investigated based on the lithium niobate straight waveguide.We propose to use the nonlinear optical process of spontaneous parametric down-conversion(SPDC)and a well-designed lithium niobate waveguide structure to generate a hyperentangled(in the polarization dimension and the energy-time dimension)two-photon state.By performing numerical simulations of the waveguide structure and calculating the possible polarization states,joint spectral amplitudes(JSA),and joint temporal amplitudes(JTA)of the generated photon pair,we show that the generated photon pair is indeed hyperentangled in both the polarization dimension and the energy-time dimension.
文摘The field of nonlinear photonics is in full development. This special issue of Photonics Research takes you through the current issues of this fast-growing field of research, drawing on the current state of the art and seeking, through a selection of articles, to outline some trends for the future.
基金supported by National Key Research and Development Program of China(2023YFA1406900)Strategic Priority Research Program(B)of Chinese Academy of Sciences(XDB0580000,XDB43010200,GJ0090406)+7 种基金National Natural Science Foundation of China(62222514,62350073,U2341226,61991440,12227901)Shanghai Science and Technology Committee(23ZR1482000,22JC1402900)Natural Science Foundation of Zhejiang Province(LR22F050004)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Youth Innovation Promotion Association(Y2021070)International Partnership Program(112GJHZ2022002FN)of Chinese Academy of SciencesShanghai Human Resources and Social Security Bureau(2022670)China Postdoctoral Science Foundation(2023T160661,2022TQ0353and 2022M713261).
文摘In the domain of spectroscopy,miniaturization efforts often face significant challenges,particularly in achieving high spectral resolution and precise construction.Here,we introduce a computational spectrometer powered by a nonlinear photonic memristor with a WSe2 homojunction.This approach overcomes traditional limitations,such as constrained Fermi level tunability,persistent dark current,and limited photoresponse dimensionality through dynamic energy band modulation driven by palladium(Pd)ion migration.The critical role of Pd ion migration is thoroughly supported by first-principles calculations,numerical simulations,and experimental verification,demonstrating its effectiveness in enhancing device performance.Additionally,we integrate this dynamic modulation with a specialized nonlinear neural network tailored to address the memristor's inherent nonlinear photoresponse.This combination enables our spectrometer to achieve an exceptional peak wavelength accuracy of o.18 nm and a spectral resolution of 2 nm within the 630-640 nm range.This development marks a significant advancement in the creation of compact,high-effciency spectroscopic instruments and offers a versatile platform for applications across diverse material systems.
基金support provided by Israel Science Foundation,grants 969/22 and 3117/23.
文摘It is commonly assumed that nonlinear frequency conversion requires lasers with high coherence;however,this assumption has constrained our broader understanding of coherence and overlooked the potential role of incoherence in nonlinear interactions.In this work,we study the synthesis of optical spatial coherence in second harmonic generation using quadratic nonlinear photonic crystals.We demonstrate a method where the second harmonic coherence is customized by employing quantitative phase retrieval and a complex square-root filter sequentially on fundamental frequency speckles.As a proof-of-concept,we experimentally show incoherent imaging of a smiley face transitioning from infrared to visible light.Moreover,we apply this method to produce two representative types of structured light beams in second harmonic generation:incoherent vortex and Airy beams.During the nonlinear synthesis of incoherent vortex beams,we have,for the first time,experimentally verified the conservation of orbital angular momentum in the nonlinear frequency conversion process of a low-coherence source.Furthermore,the generated second-harmonic incoherent Airy beam preserves the self-acceleration characteristics of its fundamental frequency counterpart,remaining unaffected by reductions in coherence.Our results not only deepen the fundamental understanding of optical coherence but also unlock exciting possibilities for applications in infrared imaging and fluorescence microscopy where optical nonlinear interactions play an important role.
基金supported by the National Natural Science Foundation of China(Nos.12274248,62275136,and 12361141815)the Natural Science Foundation of Zhejiang Province(No.LY22F050009)the K C Wong Magna Fund of Ningbo University。
文摘We fabricated a three-dimensional nonlinear photonic crystal in a Sr_(0.61)Ba_(0.39)Nb_2O_6(SBN)crystal using femtosecond laser direct writing of ferroelectric domain structures.The crystal features three layers of fork-shaped gratings,each oriented differently.These gratings convert an incident vortex beam into a second-harmonic Gaussian beam in specific directions.By altering the vortex beam's topological charge,we can control the emission direction of the second-harmonic Gaussian beam,enabling flexible all-optical switching and manipulation.This work provides a foundation for controlling photon angular momentum in nonlinear optical frequency-conversion processes.
基金supported by the National Key R&D Program of China(No.2021YFA1400800)the National Natural Science Foundation of China(Nos.12274474 and 12404376)the Natural Science Foundation of Guangdong(Nos.2022B1515020067 and 2023A1515012867)。
文摘Nonlinear photonic crystals[NPCs]with modulated second-order nonlinear coefficients[χ^([2])]enable quasi-phase-matching[QPM]for efficient frequency conversion.Traditional electric-field poling is limited to two-dimensional domain engineering and cannot achieve three-dimensional[3D]χ^([2])distributions,while femtosecond laser writing[FLW]offers greater control but introduces crystal damage.In this work,we use the pyroelectric-based fabrication process by performing the cooling step in a vacuum after FLW,suppressing thermal fluctuations,and maximizing the pyroelectric field.Vacuum cooling significantly improves domain inversion probability and uniformity compared to air cooling,making the periodicity close to electrical poling.Real-time polarized microscopy reveals improved domain growth,while nonlinear diffraction analysis confirms negligible refractive index changes.We demonstrate domain-inverted NPCs with a periodicity of 4μm,achieving QPM at near-infrared wavelengths.This method provides a scalable and efficient pathway for advanced nonlinear photonic devices.
基金supported by Beijing Natural Science Foundation(Z210004)National Key R&D Plan of China(Grant No.2021ZD0301500)+2 种基金National Natural Science Foundation of China(92150108,12293050,12304412)the highperformance computing Platform of Peking Universitythe Advanced Photonic Integrated Center(APIC)of State Key Laboratory of Advanced Optical Communication System and Networks.
文摘Chip-scale integration of optical frequency combs,particularly soliton microcombs,enables miniaturized instrumentation for timekeeping,ranging,and spectroscopy.Although soliton microcombs have been demonstrated on various material platforms,realizing complete comb functionality on photonic chips requires the co-integration of highspeed modulators and efficient frequency doublers,features that are available in a monolithic form on X-cut thin-film lithium niobate(TFLN).However,the pronounced Raman nonlinearity associated with extraordinary light in this platform has so far precluded soliton microcomb generation.Here,we report the generation of transverse-electric-polarized soliton microcombs with a 25 GHz repetition rate in high-Q microresonators on X-cut TFLN chips.By precisely orienting the racetrack microresonator relative to the optical axis,we mitigate Raman nonlinearity and enable soliton formation under continuous-wave laser pumping.Moreover,the soliton microcomb spectra are extended to 350 nm with pulsed laser pumping.This work expands the capabilities of TFLN photonics and paves the way for the monolithic integration of fast-tunable,self-referenced microcombs.
基金supported in part by the National Natural Science Foundation of China (Grant Nos. 11474108, 61378036, 61307058, 11304101, 11074078)the PhD Start-up Fund of Natural Science Foundation of Guangdong Province, China (Grant No. S2013040016320)+2 种基金the Scientific and Technological Innovation Project of Higher Education Institute, Guangdong, China (Grant No. 2013KJCX0051)the financial support from the Guangdong Natural Science Funds for Distinguished Young Scholarthe Zhujiang New-star Plan of Science & Technology in Guangzhou City (Grant No. 2014J2200008)
文摘Two-dimensional（2D） materials have emerged as attractive mediums for fabricating versatile optoelectronic devices. Recently, few-layer molybdenum disulfide（MoS2）, as a shining 2D material, has been discovered to possess both the saturable absorption effect and large nonlinear refractive index. Herein, taking advantage of the unique nonlinear optical properties of MoS2, we fabricated a highly nonlinear saturable absorption photonic device by depositing the few-layer MoS2 onto the microfiber. With the proposed MoS2 photonic device, apart from the conventional soliton patterns, the mode-locked pulses could be shaped into some new soliton patterns, namely,multiple soliton molecules, localized chaotic multipulses, and double-scale soliton clusters. Our findings indicate that the few-layer MoS2-deposited microfiber could operate as a promising highlynonlinear photonic device for the related nonlinear optics applications.
文摘The nonlinear optical （NLO） and optical limiting （OL） properties of three new structures of organic NLO vip host Poly（N-vinylcarbozole）/disperse orange 3 （PVK/DO3）, PVK/disperse orange 13 （PVK/DO13）. and PVK/disperse orange 25 （PVK/DO25） as a solution at different concentrations and as a thin-film sample are studied using continuous wave z-scan system at 532 nm. The open-aperture z-scan data of the NLO materials in the solution and thin-film samples displayed two-photon and saturable absorptions, respectively. The PVK/DO13 exhibites the largest and best values of the nonlinearities, such as n2, β, X（3） compared with those of PVK/DO3 and PVK/DO25. This nonlinearity increases as the concentration increases. Tile results indicate that these NLO materials are good candidates for optical switching and OL devices.
基金supported by the National Natural Science Foundation of China(Nos.61905124,11974196,and 61905125)the Australian Research Council(No.DP19010774)+2 种基金the Qatar National Research Fund(No.NPRP 12S-0205190047)the Yongjiang Scholar Foundation of Ningbothe K.C.Wong Magna Fund of Ningbo University。
文摘The nonlinear Talbot effect is a near-field nonlinear diffraction phenomenon in which the self-imaging of periodic objects is formed by the second harmonics of the incident laser beam. We demonstrate the first, to the best of our knowledge, example of nonlinear Talbot self-healing, i.e., the capability of creating defect-free images from faulty nonlinear optical structures. In particular, we employ the tightly focused femtosecond infrared optical pulses to fabricate LiNbO_(3) nonlinear photonic crystals and show that the defects in the form of the missing points of two-dimensional square and hexagonal periodic structures are restored in the second harmonic images at the first nonlinear Talbot plane. The observed nonlinear Talbot self-healing opens up new possibilities for defect-tolerant optical lithography and printing.
基金supported by the National Natural Science Foundation of China(Nos.62275136,61905124,12274248,and 62090063)the Natural Science Foundation of Zhejiang Province(No.LY22F050009)+1 种基金the Yongjiang Scholar Foundation of Ningbothe K.C.Wong Magna Fund of Ningbo University。
文摘The design of nonlinear photonic Vogel's spiral based on quasi-crystal theory was demonstrated.Two main parameters of Vogel's spiral were arranged to obtain multi-reciprocal circles.Typical structure was fabricated by the near-infrared femtosecond laser poling technique,forming a nonlinear photonic structure,and multiple ring-like nonlinear Raman±Nath second-harmonic generation processes were realized and analyzed in detail.The structure for the cascaded thirdharmonic generation process was predicted.The results could help deepen the understanding of Vogel's spiral and quasi-crystal and pave the way for the combination of quasi-crystal theory with more aperiodic structures.
基金supported by the National Natural Science Foundation of China(Nos.12274248,62275136,and 12361141815)the Natural Science Foundation of Zhejiang Province(No.LY22F050009)the K.C.Wong Magna Fund of Ningbo University.
文摘A 3D nonlinear photonic crystal containing four parallel segments of periodicχ^((2))grating structure is fabricated employing the femtosecond laser poling of ferroelectric Ca_(0.28)Ba_(0.72)Nb_(2)O_(6) crystal.The second harmonic generation from this foursegment structure is studied with a fundamental Gaussian wave.By tuning the wavelength of the fundamental wave,the second harmonic varies from the Laguerre-Gaussian beam(topological charge l_(c)=1)to the higher-order Hermite-Gaussian beam and Laguerre-Gaussian again(l_(c)=−1).This effect is caused by the wavelength-dependent phase delays introduced by the four-grating structure.Our study contributes to a deeper understanding of nonlinear wave interactions in 3D nonlinear photonic crystals.It also offers new possibilities for special beam generation at new frequencies and their control.
文摘We investigate in this paper the influence of slow light on the balance between the Kerr and two-photon absorption(TPA) processes in silicon slotted hybrid nonlinear waveguides. Three typical silicon photonic waveguide geometries are studied to estimate the influence of the light slow-down factor on the mode field overlap with the silicon region, as well as on the complex effective nonlinear susceptibility. It is found that slotted photonic crystal modes tend to focalize in their hollow core with increasing group index(n_G) values. Considering a hybrid integration of nonlinear polymers in such slotted waveguides, a relative decrease of the TPA process by more factor of 2 is predicted from n_G=10 to n_G=50. As a whole, this work shows that the relative influence of TPA decreases for slotted waveguides operating in the slow light regime, making them a suitable platform for third-order nonlinear optics.
基金National Natural Science Foundation of China(12434016,11974119)Science and Technology Project of Guangdong(2020B010190001)National Funded Postdoctoral Researcher Program(GZB20240785)。
文摘Submicron-thick thin-film lithium niobate(TFLN)has emerged as a promising platform for nonlinear integrated photonics.In this work,we demonstrate the efficient simultaneous generation of broadband 2nd–8th harmonics in chirped periodically poled(CPP)TFLN.This is achieved through the synergistic effects of cascadedχ^((2))nonlinear up-conversion andχ^((3))self-phase modulation,driven by near-infrared femtosecond pulses with a central wavelength of 2100 nm and a pulse energy of 1.2μJ.Remarkably,the 7th and 8th harmonics extend into the deep ultraviolet(DUV)region,reaching wavelengths as short as 250 nm.The 3rd–8th harmonic spectra seamlessly connect,forming a broadband supercontinuum spanning from the DUV to the visible range(250–800 nm,-25 d B),with an on-chip conversion efficiency of 19%(0.23μJ).This achievement is attributed to the CPP-TFLN providing multiple broadband reciprocal lattice vector bands,enabling quasi-phase matching for a series ofχ^((2))nonlinear processes,including second harmonic generation(SHG),cascaded SHG,and third harmonic generation.Furthermore,we demonstrated the significant role of cascadedχ^((2))phase-mismatched nonlinear processes in high-harmonic generation(HHG).Our work unveils the intricate and diverse nonlinear optical interactions in TFLN,offering a clear path toward efficient on-chip HHG and compact coherent white-light sources extending into the DUV.
基金supported by the National Natural Science Foundation of China(Grant No.61605106)Funded projects for the Academic Leader and Academic Backbones,Shaanxi Normal University(No.18QNGG006)+3 种基金Shaanxi International Cooperation Project(No.2020KW-005)Starting Grants of Shaanxi Normal University(Nos.1112010209 and 1110010717)Open Research Fund of State Key Laboratory of Transient Optics and Photonics,Chinese Academy of Sciences(No.SKLST201809)Fundamental Research Funds for the Central Universities(Nos.GK201802006 and 2018CSLY005).
文摘In this paper,we have proposed and demonstrated the generation of passively mode-locked pulses and dissipative soliton resonance in an erbium-doped fiber laser based on Fe3O4 nanoparticles as saturable absorbers.We obtained self-starting mode-locked pulses with fundamental repetition frequency of 7.69 MHz and center wavelength of 1561 nm.The output of a pulsed laser has spectral width of 0.69 nm and pulse duration of 14 ns with rectangular pulse profile at the pump power of 190 mW.As far as we know,this is the first time that Fe3O4 nanoparticles have been developed as low-dimensional materials for passive mode-locking with rectangular pulse.Our experiments have confirmed that Fe3O4 has a wide prospect as a nonlinear photonics device for ultrafast fiber laser applications.
