Common-signal-induced synchronization of semiconductor lasers have promising applications in physical-layer secure transmission with high speed and compatibility with the current fiber communication.Here,we propose an...Common-signal-induced synchronization of semiconductor lasers have promising applications in physical-layer secure transmission with high speed and compatibility with the current fiber communication.Here,we propose an ultra-long-distance laser synchronization scheme by utilizing random digital optical communication signal as the common drive signal.By utilizing the long-haul optical coherent communication techniques,high-fdelity fiber transmission of the digital drive can be achieved and thus ultra-long-distance synchronization is expected.Experiments were implemented with distributed feedback lasers injected by a random-digital phase-modulated drive light.Results show that high-quality synchronization can be achieved as the drive signal rate is larger than the laser relaxation frequency and the transmission bit error ratio is below a critical value.Chaos synchronization over 8191-km fiber transmission was experimentally achieved.Compared to traditional common-signal-induced synchronization using analog drive signal such as chaos,the distance is increased by 8 times,and complicated hardware devices for channel impairment compensation are no longer required.In addition,the proposed method does not sacrifice communication capacity like traditional methods which need a channel to transmit analog drive signal.It is therefore believed that this common-digital-signal induced laser synchronization paves a way for secure backbone and submarine transmission.展开更多
The Kerr nonlinearity in two-dimensional(2D)nanomaterials is emerging as an appealing and intriguing research area due to their prominent light processing,modulation,and manipulation abilities.In this contribution,2D ...The Kerr nonlinearity in two-dimensional(2D)nanomaterials is emerging as an appealing and intriguing research area due to their prominent light processing,modulation,and manipulation abilities.In this contribution,2D black arsenic-phosphorus(B-AsP)nanosheets(NSs)were applied in nonlinear photonic devices based on spatial self-phase modula-tion(SSPM)method.By applying the Kerr nonlinearity in 2D B-AsP,an all-optical phase-modulated system is proposed to realize the functions of“on”and“off”in all-optical switching.By using the same all-optical phase-modulated system,another optical logic gate is proposed,and the logical“or”function is obtained based on the 2D B-AsP NSs dispersions.Moreover,by using the SSPM method,a 2D B-AsP/SnS_(2) hybrid structure is fabricated,and the result illustrates that the hybrid structure possesses the ability of the unidirectional nonlinear excitation,which helps in obtaining the function of spatial asymmetric light propagation.This function is considered an important prerequisite for the realization of diode functionalization,which is believed to be a factor in important basis for the design of isolators as well.The initial investig-ations indicate that 2D B-AsP is applicable for designing optical logical devices,which can be considered as an import-ant development in all-optical information processing.展开更多
The dynamic gain of a few-mode erbium-doped fiber amplifier(FM-EDFA)is vital for the long-haul mode division multiplexing(MDM)transmission.Here,we investigate the mode-dependent dynamic gain of an FM-EDFA under variou...The dynamic gain of a few-mode erbium-doped fiber amplifier(FM-EDFA)is vital for the long-haul mode division multiplexing(MDM)transmission.Here,we investigate the mode-dependent dynamic gain of an FM-EDFA under various manipulations of the pump mode.First,we numerically calculate the gain variation with respect to the input signal power,where a modedependent saturation input power occurs under different pump modes.Even under the fixed intensity profile of the pump laser,the saturation input power of each spatial mode is different.Moreover,high-order mode pumping leads to a compression of the linear amplification region,even though it is beneficial for the mitigation of the differential modal gain(DMG)arising in all guided modes.Then,we develop an all-fiber 3-mode EDFA,where the fundamental mode of the pump laser can be efficiently converted to the LP_(11)mode using the all-fiber mode-selective coupler(MSC).In comparison with the traditional LP_(01)pumping scheme,the DMG at 1550 nm can be mitigated from 1.61 dB to 0.97 dB under the LP_(11)mode pumping,while both an average gain of 19.93 dB and a DMG of less than 1 dB can be achieved from 1530 nm to 1560 nm.However,the corresponding signal input saturation powers are reduced by 0.3 dB for the LP_(01)mode and 1.6 dB for the LP_(11)mode,respectively.Both theoretical and experimental results indicate that a trade-off occurs between the DMG mitigation and the extension of the linear amplification range when the intensity profile of pump laser is manipulated.展开更多
Dispersion management in guided wave optics is of vital importance for various applications.Topological photonics opens new horizons for manipulating unidirectional guided waves utilizing edge states.However,the exper...Dispersion management in guided wave optics is of vital importance for various applications.Topological photonics opens new horizons for manipulating unidirectional guided waves utilizing edge states.However,the experimental observation of spatiotemporal dynamics for guided waves with on-demand dispersion in topological photonic crystal is an important issue awaiting exploitation.Herein,we experimentally investigate the spatiotemporal properties of topological surface states with on-demand dispersion,where they are supported by a truncated valley photonic crystal with surface modulation.We observe the electromagnetic dynamics of surface states with typical dispersions,where dynamical trapping of an electromagnetic pulse mediated by the unidirectional surface state with flat dispersion and backward beam routing using reversed dispersion properties are achieved in photonic crystal slabs.Both numerical and experimental results substantiate the ultimate dispersion management for topological surface states,which could pave new ways for the manipulation of electromagnetic waves on the surface of photonic devices.展开更多
The intermodal nonlinear coefficient is an important parameter to analytically describe few-mode fiber(FMF) nonlinearity when the nonlinear interaction arising in the FMF is exploited for various applications. Here, w...The intermodal nonlinear coefficient is an important parameter to analytically describe few-mode fiber(FMF) nonlinearity when the nonlinear interaction arising in the FMF is exploited for various applications. Here, we experimentally characterize the intermodal nonlinear coefficient based on continuous-wave cross-phase modulation, without a priori knowledge of the intramodal nonlinear coefficient for the FMF under test. Based on the derived equation, we examine the impact of the pump modulation scheme and the wavelength spacing between the probe and pump on the precise measurement of the intermodal nonlinear coefficient. Compared with double sideband(DSB) modulation, the pump modulated with carrier-suppressed DSB scheme leads to an underestimation of measurement results, due to the coexistence of unnecessary nonlinear interactions. Finally, the intermodal nonlinear coefficient of a 1.9-km FMF supporting two mode groups is experimentally characterized and is in good agreement with the theoretically calculated values. Due to the random birefringence fluctuation, the average value of 4/3 to describe the intermodal nonlinear interaction arising in weakly coupled FMF by the commonly used Manakov equation is experimentally verified.展开更多
Lithium niobate has received interest in nonlinear frequency conversion due to its wide transparency window,from ultraviolet to mid-infrared spectral regions,and large second-order nonlinear susceptibility.However,its...Lithium niobate has received interest in nonlinear frequency conversion due to its wide transparency window,from ultraviolet to mid-infrared spectral regions,and large second-order nonlinear susceptibility.However,its nanostructure is generally difficult to etch,resulting in low-Q resonance and lossy nanostructures for second harmonic generation.By applying the concept of bound states in the continuum,we performed theoretical and experimental investigations on high-Q resonant etchless thin-film lithium niobate with Si O_(2) nanostructures on top for highly efficient second harmonic generation.In the fabricated nanostructured devices,a resonance with a Q factor of 980 leads to the strong enhancement of second harmonic generation by over 1500 times compared with that in unpatterned lithium niobate thin film.Although the pump slightly deviates from central resonance,an absolute conversion efficiency of 6.87×10^(-7) can be achieved with the fundamental pump peak intensity of 44.65 MW/cm^(2),thus contributing to the normalized conversion efficiency of 1.54×10^(-5)cm^(2)/GW.Our work establishes an etchless lithium niobate device for various applications,such as integrated nonlinear nanophotonics,terahertz frequency generation,and quantum information processing.展开更多
Higher-order Poincarésphere(HOPS) beams with spatially variable polarization and phase distributions are opening up a host of unique applications in areas ranging from optical communication to microscopy.However,...Higher-order Poincarésphere(HOPS) beams with spatially variable polarization and phase distributions are opening up a host of unique applications in areas ranging from optical communication to microscopy.However, the flexible generation of these beams with high peak power from compact laser systems remains a challenge. Here, we demonstrate the controlled generation of HOPS beams based on coherent beam combination from an Yb-doped multicore fiber(MCF) amplifier. Using a spatial light modulator to adaptively adjust the wavefront and polarization of the signals seeded into the individual cores of the MCF various structured beams(including cylindrical vector beams and first-and second-order vortex beams) were generated with peak powers up to 14 k W for ~92 ps pulses.展开更多
The regeneration of the injured nerve and recovery of its function have brought attention in the medical field. Electrical stimulation(ES) can enhance the cellular biological behavior and has been widely studied in th...The regeneration of the injured nerve and recovery of its function have brought attention in the medical field. Electrical stimulation(ES) can enhance the cellular biological behavior and has been widely studied in the treatment of neurological diseases. Microfluidic technology can provide a cell culture platform with the well-controlled environment. Here a novel microfluidic/microelectrode composite microdevice was developed by embedding the microelectrodes to the microfluidic platform, in which microfluidics provided a controlled cell culture platform, and ES promoted the NSCs proliferation. We performed ES on rat neural stem cells(NSCs) to observe the effect on their growth, differentiation, proliferation, and preliminary explored the ES influence on cells in vitro. The results of immunofluorescence showed that ES had no significant effect on the NSCs specific expression, and the NSCs specific expression reached 98.9%± 0.4% after three days of ES. In addition, ES significantly promoted cell growth and the cell proliferation rate reached 49.41%. To conclude, the microfluidic/microelectrode composite microdevice can play a positive role in the nerve injury repair and fundamental research of neurological diseases.展开更多
Random bit generators are critical for information security,cryptography,stochastic modeling,and simulations.Speed and scalability are key challenges faced by current physical random bit generation.Herein,we propose a...Random bit generators are critical for information security,cryptography,stochastic modeling,and simulations.Speed and scalability are key challenges faced by current physical random bit generation.Herein,we propose a massively parallel scheme for ultrafast random bit generation towards rates of order 100 terabit per second based on a single micro-ring resonator.A modulation-instability-driven chaotic comb in a micro-ring resonator enables the simultaneous generation of hundreds of independent and unbiased random bit streams.A proof-of-concept experiment demonstrates that using our method,random bit streams beyond 2 terabit per second can be successfully generated with only 7 comb lines.This bit rate can be easily enhanced by further increasing the number of comb lines used.Our approach provides a chip-scale solution to random bit generation for secure communication and high-performance computation,and offers superhigh speed and large scalability.展开更多
The mode-division multiplexing technique combined with a few-mode erbium-doped fiber amplifier(FM-EDFA)demonstrates significant potential for solving the capacity limitation of standard single-mode fiber(SSMF)transmis...The mode-division multiplexing technique combined with a few-mode erbium-doped fiber amplifier(FM-EDFA)demonstrates significant potential for solving the capacity limitation of standard single-mode fiber(SSMF)transmission systems.However,the differential mode gain(DMG)arising in the FM-EDFA fundamentally limits its transmission capacity and length.Herein,an innovative DMG equalization strategy using femtosecond laser micromachining to adjust the refractive index(RI)is presented.Variable mode-dependent attenuations can be achieved according to the DMG profile of the FM-EDFA,enabling DMG equalization.To validate the proposed strategy,DMG equalization of the commonly used FM-EDFA configuration was investigated.Simulation results revealed that by optimizing both the length and RI modulation depth of the femtosecond laser-tailoring area,the maximum DMG(DMGmax)among the 3 linear-polarized(LP)mode-group was mitigated from 10 dB to 1.52 dB,whereas the average DMG(DMGave)over the C-band was reduced from 8.95 dB to 0.78 dB.Finally,a 2-LP mode-group DMG equalizer was experimentally demonstrated,resulting in a reduction of the DMGmax from 2.09 dB to 0.46 dB,and a reduction of DMGave over the C band from 1.64 dB to 0.26 dB,with only a 1.8 dB insertion loss.Moreover,a maximum range of variable DMG equalization was achieved with 5.4 dB,satisfying the requirements of the most commonly used 2-LP mode-group amplification scenarios.展开更多
High-speed polarization management is highly desirable for many applications,such as remote sensing,telecommunication,and medical diagnosis.However,most of the approaches for polarization management rely on bulky opti...High-speed polarization management is highly desirable for many applications,such as remote sensing,telecommunication,and medical diagnosis.However,most of the approaches for polarization management rely on bulky optical components that are slow to respond,cumbersome to use,and sometimes with high drive voltages.Here,we overcome these limitations by harnessing photonic integrated circuits based on thin-film lithium niobate platform.We successfully realize a portfolio of thin-film lithium niobate devices for essential polarization management functionalities,including arbitrary polarization generation,fast polarization measurement,polarization scrambling,and automatic polarization control.The present devices feature ultra-fast control speeds,low drive voltages,low optical losses and compact footprints.Using these devices,we achieve high fidelity polarization generation with a polarization extinction ratio up to 41.9 dB and fast polarization scrambling with a scrambling rate up to 65 Mrad s−1,both of which are best results in integrated optics.We also demonstrate the endless polarization state tracking operation in our devices.The demonstrated devices unlock a drastically new level of performance and scales in polarization management devices,leading to a paradigm shift in polarization management.展开更多
The self-mixing interferometry(SMI)technique is an emerging sensing technology in microscale particle classification.However,due to the nature of the SMI effect raised by a microscattering particle,the signal analysis...The self-mixing interferometry(SMI)technique is an emerging sensing technology in microscale particle classification.However,due to the nature of the SMI effect raised by a microscattering particle,the signal analysis suffers from many problems compared with a macro target,such as lower signal-to-noise ratio(SNR),short transit time,and time-varying modulation strength.Therefore,the particle sizing measurement resolution is much lower than the one in typical displacement measurements.To solve these problems,in this paper,first,a theoretical model of the phase variation of a singleparticle SMI signal burst is demonstrated in detail.The relationship between the phase variation and the particle size is investigated,which predicts that phase observation could be another alternative for particle detection.Second,combined with continuous wavelet transform and Hilbert transform,a novel phase-unwrapping algorithm is proposed.This algorithm can implement not only efficient individual burst extraction from the noisy raw signal,but also precise phase calculation for particle sizing.The measurement shows good accuracy over a range from 100 nm to 6μm with our algorithm,proving that our algorithm enables a simple and reliable quantitative particle characteristics retrieval and analysis methodology for microscale particle detection in biomedical or laser manufacturing fields.展开更多
Strong coupling(SC) between two resonant plasmon modes can result in the formation of new hybrid modes exhibiting Rabi splitting with strong energy exchange at the nanoscale. However, normal Rabi splitting is often li...Strong coupling(SC) between two resonant plasmon modes can result in the formation of new hybrid modes exhibiting Rabi splitting with strong energy exchange at the nanoscale. However, normal Rabi splitting is often limited to ~50–320 me V due to the short lifetime of the plasmon mode. Here, we theoretically demonstrate a record Rabi splitting energy as large as 805 me V arising from the SC between the high-Q plasmonic whispering gallery mode and high-Q cavity plasmon resonance supported by a spherical hyperbolic metamaterial cavity,which consists of a dielectric nanosphere core wrapped in 7 alternating layers of silver/dielectric materials.In addition, the new hybrid modes formed by the SC are shown to exhibit an extralong lifetime of up to 71.9–81.6 fs, with the large electric field intensity enhancement at both the dielectric core and the dielectric layers. More importantly, the spectral ranges of SC can be tuned across an ultrabroad range from the visible to the near-IR by simply changing the dielectric core size. These findings may have potential applications in bright single-photon sources.展开更多
Realizing high-fidelity optical information transmission through a scattering medium is of vital importance in both science and applications,such as short-range fiber communication and optical encryption.Theoretically...Realizing high-fidelity optical information transmission through a scattering medium is of vital importance in both science and applications,such as short-range fiber communication and optical encryption.Theoretically,an input wavefront can be reconstructed by inverting the transmission matrix of the scattering medium.However,this deterministic method for retrieving light field information encoded in the wavefront has not yet been experimentally demonstrated.Herein,we demonstrate light field information transmission through different scattering media with near-unity fidelity.Multi-dimensional optical information can be delivered through either a multimode fiber or a ground glass without relying on any averaging or approximation,where their Pearson correlation coefficients can be up to 99%.展开更多
We proposed and experimentally demonstrated an all-fiber sensor for measuring bend with high sensitivity based on a ring core fiber(RCF)modal interferometer.The sensor was fabricated by splicing a segment of RCF betwe...We proposed and experimentally demonstrated an all-fiber sensor for measuring bend with high sensitivity based on a ring core fiber(RCF)modal interferometer.The sensor was fabricated by splicing a segment of RCF between two pieces of multimode fiber(MMF)and single-mode fiber(SMF)at the ends of the MMF as lead-in and lead-out.Due to the first segment of the MMF,the transmitted light is coupled into the ring core,silica center,and cladding of the RCF,exciting multiple modes in the RCF.By the modal interferences in the structure,bending sensing can be realized by interrogating the intensity of the interference dip.Experimental results show a high bending sensitivity of-25.63 dB/m^(-1)in the range of 1.0954 m^(-1)to1.4696 m^(-1).In addition,the advantages of the bend sensor,such as small size,low temperature sensitivity,and simple fabrication process,can be used for curvature measurement in building health monitoring.展开更多
基金supported by National Natural Science Foundation of China(62035009,U22A2087)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams of"The Pearl River Talent Recruitment Program"(2019ZT08X340)+2 种基金The Major Key Project of PCL(PCL2021A14)Shanxi"1331 Project"Key Innovative TeamDevelopment Fund in Science and Technology of Shanxi Province(YDZJSX2021A009).
文摘Common-signal-induced synchronization of semiconductor lasers have promising applications in physical-layer secure transmission with high speed and compatibility with the current fiber communication.Here,we propose an ultra-long-distance laser synchronization scheme by utilizing random digital optical communication signal as the common drive signal.By utilizing the long-haul optical coherent communication techniques,high-fdelity fiber transmission of the digital drive can be achieved and thus ultra-long-distance synchronization is expected.Experiments were implemented with distributed feedback lasers injected by a random-digital phase-modulated drive light.Results show that high-quality synchronization can be achieved as the drive signal rate is larger than the laser relaxation frequency and the transmission bit error ratio is below a critical value.Chaos synchronization over 8191-km fiber transmission was experimentally achieved.Compared to traditional common-signal-induced synchronization using analog drive signal such as chaos,the distance is increased by 8 times,and complicated hardware devices for channel impairment compensation are no longer required.In addition,the proposed method does not sacrifice communication capacity like traditional methods which need a channel to transmit analog drive signal.It is therefore believed that this common-digital-signal induced laser synchronization paves a way for secure backbone and submarine transmission.
基金supports from the National Natural Science Foundation of China(NSFC)(61435010 and 21773168)the Science and Technique Planning Project of Guangdong Province(Grant No.2016B050501005)+1 种基金the Science and Technology Innovation Commission of Shenzhen(JCYJ20170302153323978 and JCYJ201704101719588539)the Science and Technology Development Fund(No.007/2017/A1 and132/2017/A3),Ma-cao SAR,China.
文摘The Kerr nonlinearity in two-dimensional(2D)nanomaterials is emerging as an appealing and intriguing research area due to their prominent light processing,modulation,and manipulation abilities.In this contribution,2D black arsenic-phosphorus(B-AsP)nanosheets(NSs)were applied in nonlinear photonic devices based on spatial self-phase modula-tion(SSPM)method.By applying the Kerr nonlinearity in 2D B-AsP,an all-optical phase-modulated system is proposed to realize the functions of“on”and“off”in all-optical switching.By using the same all-optical phase-modulated system,another optical logic gate is proposed,and the logical“or”function is obtained based on the 2D B-AsP NSs dispersions.Moreover,by using the SSPM method,a 2D B-AsP/SnS_(2) hybrid structure is fabricated,and the result illustrates that the hybrid structure possesses the ability of the unidirectional nonlinear excitation,which helps in obtaining the function of spatial asymmetric light propagation.This function is considered an important prerequisite for the realization of diode functionalization,which is believed to be a factor in important basis for the design of isolators as well.The initial investig-ations indicate that 2D B-AsP is applicable for designing optical logical devices,which can be considered as an import-ant development in all-optical information processing.
基金supported by the National Key R&D Program of China(No.2018YFB1800903)the National Natural Science Foundation of China(No.U22A2087)+1 种基金the Guangdong Introducing Innovative and Entrepreneurial Teams of the Pearl River Talent Recruitment Program(No.2021ZT09X044)the Guangdong Provincial Key Laboratory of Photonics Information Technology(No.2020B121201011)。
文摘The dynamic gain of a few-mode erbium-doped fiber amplifier(FM-EDFA)is vital for the long-haul mode division multiplexing(MDM)transmission.Here,we investigate the mode-dependent dynamic gain of an FM-EDFA under various manipulations of the pump mode.First,we numerically calculate the gain variation with respect to the input signal power,where a modedependent saturation input power occurs under different pump modes.Even under the fixed intensity profile of the pump laser,the saturation input power of each spatial mode is different.Moreover,high-order mode pumping leads to a compression of the linear amplification region,even though it is beneficial for the mitigation of the differential modal gain(DMG)arising in all guided modes.Then,we develop an all-fiber 3-mode EDFA,where the fundamental mode of the pump laser can be efficiently converted to the LP_(11)mode using the all-fiber mode-selective coupler(MSC).In comparison with the traditional LP_(01)pumping scheme,the DMG at 1550 nm can be mitigated from 1.61 dB to 0.97 dB under the LP_(11)mode pumping,while both an average gain of 19.93 dB and a DMG of less than 1 dB can be achieved from 1530 nm to 1560 nm.However,the corresponding signal input saturation powers are reduced by 0.3 dB for the LP_(01)mode and 1.6 dB for the LP_(11)mode,respectively.Both theoretical and experimental results indicate that a trade-off occurs between the DMG mitigation and the extension of the linear amplification range when the intensity profile of pump laser is manipulated.
基金National Natural Science Foundation of China(62222505,62335005)Guangdong Introducing Innovative,Entrepreneurial Teams of the Pearl River Talent Recruitment Program(2019ZT08X340).
文摘Dispersion management in guided wave optics is of vital importance for various applications.Topological photonics opens new horizons for manipulating unidirectional guided waves utilizing edge states.However,the experimental observation of spatiotemporal dynamics for guided waves with on-demand dispersion in topological photonic crystal is an important issue awaiting exploitation.Herein,we experimentally investigate the spatiotemporal properties of topological surface states with on-demand dispersion,where they are supported by a truncated valley photonic crystal with surface modulation.We observe the electromagnetic dynamics of surface states with typical dispersions,where dynamical trapping of an electromagnetic pulse mediated by the unidirectional surface state with flat dispersion and backward beam routing using reversed dispersion properties are achieved in photonic crystal slabs.Both numerical and experimental results substantiate the ultimate dispersion management for topological surface states,which could pave new ways for the manipulation of electromagnetic waves on the surface of photonic devices.
基金supported by the National Natural Science Foundation of China (No.U22A2087)the Guangdong Introducing Innovative and Entrepreneurial Teams of the Pearl River Talent Recruitment Program (No.2021ZT09X044)。
文摘The intermodal nonlinear coefficient is an important parameter to analytically describe few-mode fiber(FMF) nonlinearity when the nonlinear interaction arising in the FMF is exploited for various applications. Here, we experimentally characterize the intermodal nonlinear coefficient based on continuous-wave cross-phase modulation, without a priori knowledge of the intramodal nonlinear coefficient for the FMF under test. Based on the derived equation, we examine the impact of the pump modulation scheme and the wavelength spacing between the probe and pump on the precise measurement of the intermodal nonlinear coefficient. Compared with double sideband(DSB) modulation, the pump modulated with carrier-suppressed DSB scheme leads to an underestimation of measurement results, due to the coexistence of unnecessary nonlinear interactions. Finally, the intermodal nonlinear coefficient of a 1.9-km FMF supporting two mode groups is experimentally characterized and is in good agreement with the theoretically calculated values. Due to the random birefringence fluctuation, the average value of 4/3 to describe the intermodal nonlinear interaction arising in weakly coupled FMF by the commonly used Manakov equation is experimentally verified.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61775084, and 62075088)the National Safety Academic Fund (Grant No. U2030103)+2 种基金the Natural Science Foundation of Guangdong Province (Grant Nos. 2020A1515010791, and 2021A0505030036)the Open Fund of Guangdong Provincial Key Laboratory of Information Photonics Technology of Guangdong University of Technology (Grant No. GKPT20-03)the Fundamental Research Funds for the Central Universities (Grant Nos. 21622107, and 21622403)。
文摘Lithium niobate has received interest in nonlinear frequency conversion due to its wide transparency window,from ultraviolet to mid-infrared spectral regions,and large second-order nonlinear susceptibility.However,its nanostructure is generally difficult to etch,resulting in low-Q resonance and lossy nanostructures for second harmonic generation.By applying the concept of bound states in the continuum,we performed theoretical and experimental investigations on high-Q resonant etchless thin-film lithium niobate with Si O_(2) nanostructures on top for highly efficient second harmonic generation.In the fabricated nanostructured devices,a resonance with a Q factor of 980 leads to the strong enhancement of second harmonic generation by over 1500 times compared with that in unpatterned lithium niobate thin film.Although the pump slightly deviates from central resonance,an absolute conversion efficiency of 6.87×10^(-7) can be achieved with the fundamental pump peak intensity of 44.65 MW/cm^(2),thus contributing to the normalized conversion efficiency of 1.54×10^(-5)cm^(2)/GW.Our work establishes an etchless lithium niobate device for various applications,such as integrated nonlinear nanophotonics,terahertz frequency generation,and quantum information processing.
基金Engineering and Physical Sciences Research Council(EP/N00762X/1,EP/P027644/1,EP/P030181/1,EP/T019441/1)H2020 European Research Council(802682)+1 种基金China Scholarship Council(202006840003)Guangdong Introducing Innovative and Entrepreneurial Teams of“The Pearl River Talent Recruitment Program”(2021ZT09X044)
文摘Higher-order Poincarésphere(HOPS) beams with spatially variable polarization and phase distributions are opening up a host of unique applications in areas ranging from optical communication to microscopy.However, the flexible generation of these beams with high peak power from compact laser systems remains a challenge. Here, we demonstrate the controlled generation of HOPS beams based on coherent beam combination from an Yb-doped multicore fiber(MCF) amplifier. Using a spatial light modulator to adaptively adjust the wavefront and polarization of the signals seeded into the individual cores of the MCF various structured beams(including cylindrical vector beams and first-and second-order vortex beams) were generated with peak powers up to 14 k W for ~92 ps pulses.
基金financially supported by the Key Scientific and Technological Projects of the Beijing Education Commission (No.KZ201910005009)。
文摘The regeneration of the injured nerve and recovery of its function have brought attention in the medical field. Electrical stimulation(ES) can enhance the cellular biological behavior and has been widely studied in the treatment of neurological diseases. Microfluidic technology can provide a cell culture platform with the well-controlled environment. Here a novel microfluidic/microelectrode composite microdevice was developed by embedding the microelectrodes to the microfluidic platform, in which microfluidics provided a controlled cell culture platform, and ES promoted the NSCs proliferation. We performed ES on rat neural stem cells(NSCs) to observe the effect on their growth, differentiation, proliferation, and preliminary explored the ES influence on cells in vitro. The results of immunofluorescence showed that ES had no significant effect on the NSCs specific expression, and the NSCs specific expression reached 98.9%± 0.4% after three days of ES. In addition, ES significantly promoted cell growth and the cell proliferation rate reached 49.41%. To conclude, the microfluidic/microelectrode composite microdevice can play a positive role in the nerve injury repair and fundamental research of neurological diseases.
基金National Natural Science Foundation of China(61927811,62175177,62322504,62075238,and U19A2076)Innovation Program for Quantum Science and Technology(2021ZD0300701,2021ZD0301500)+1 种基金Program for Guangdong Introducing Innovative and Entrepreneurial TeamsStability Program of Science and Technology on Communication Security Laboratory(2022).
文摘Random bit generators are critical for information security,cryptography,stochastic modeling,and simulations.Speed and scalability are key challenges faced by current physical random bit generation.Herein,we propose a massively parallel scheme for ultrafast random bit generation towards rates of order 100 terabit per second based on a single micro-ring resonator.A modulation-instability-driven chaotic comb in a micro-ring resonator enables the simultaneous generation of hundreds of independent and unbiased random bit streams.A proof-of-concept experiment demonstrates that using our method,random bit streams beyond 2 terabit per second can be successfully generated with only 7 comb lines.This bit rate can be easily enhanced by further increasing the number of comb lines used.Our approach provides a chip-scale solution to random bit generation for secure communication and high-performance computation,and offers superhigh speed and large scalability.
基金supported by the National Natural Science Foundation of China(62305071)China Postdoctoral Science Foundation(2023M740747)Guangdong Introducing Innovative and Entrepreneurial Teams of“The Pearl River Talent Recruitment Program”(2021ZT09X044).
文摘The mode-division multiplexing technique combined with a few-mode erbium-doped fiber amplifier(FM-EDFA)demonstrates significant potential for solving the capacity limitation of standard single-mode fiber(SSMF)transmission systems.However,the differential mode gain(DMG)arising in the FM-EDFA fundamentally limits its transmission capacity and length.Herein,an innovative DMG equalization strategy using femtosecond laser micromachining to adjust the refractive index(RI)is presented.Variable mode-dependent attenuations can be achieved according to the DMG profile of the FM-EDFA,enabling DMG equalization.To validate the proposed strategy,DMG equalization of the commonly used FM-EDFA configuration was investigated.Simulation results revealed that by optimizing both the length and RI modulation depth of the femtosecond laser-tailoring area,the maximum DMG(DMGmax)among the 3 linear-polarized(LP)mode-group was mitigated from 10 dB to 1.52 dB,whereas the average DMG(DMGave)over the C-band was reduced from 8.95 dB to 0.78 dB.Finally,a 2-LP mode-group DMG equalizer was experimentally demonstrated,resulting in a reduction of the DMGmax from 2.09 dB to 0.46 dB,and a reduction of DMGave over the C band from 1.64 dB to 0.26 dB,with only a 1.8 dB insertion loss.Moreover,a maximum range of variable DMG equalization was achieved with 5.4 dB,satisfying the requirements of the most commonly used 2-LP mode-group amplification scenarios.
基金supported by the National Key Research and Development Program of China(2019YFB1803900 and 2019YFA0705000)National Natural Science Foundation of China(11690031 and 11761131001)+2 种基金Key R&D Program of Guangdong Province(2018B030329001)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X121)Key-Area Research and Development Program of Guangdong Province(2019B121204003).
文摘High-speed polarization management is highly desirable for many applications,such as remote sensing,telecommunication,and medical diagnosis.However,most of the approaches for polarization management rely on bulky optical components that are slow to respond,cumbersome to use,and sometimes with high drive voltages.Here,we overcome these limitations by harnessing photonic integrated circuits based on thin-film lithium niobate platform.We successfully realize a portfolio of thin-film lithium niobate devices for essential polarization management functionalities,including arbitrary polarization generation,fast polarization measurement,polarization scrambling,and automatic polarization control.The present devices feature ultra-fast control speeds,low drive voltages,low optical losses and compact footprints.Using these devices,we achieve high fidelity polarization generation with a polarization extinction ratio up to 41.9 dB and fast polarization scrambling with a scrambling rate up to 65 Mrad s−1,both of which are best results in integrated optics.We also demonstrate the endless polarization state tracking operation in our devices.The demonstrated devices unlock a drastically new level of performance and scales in polarization management devices,leading to a paradigm shift in polarization management.
基金supported by the National Natural Science Foundation of China(Nos.61905005 and 52175375)the General Program of Science and Technology Development Project of Beijing Municipal Education Commission(No.KM202110005004)。
文摘The self-mixing interferometry(SMI)technique is an emerging sensing technology in microscale particle classification.However,due to the nature of the SMI effect raised by a microscattering particle,the signal analysis suffers from many problems compared with a macro target,such as lower signal-to-noise ratio(SNR),short transit time,and time-varying modulation strength.Therefore,the particle sizing measurement resolution is much lower than the one in typical displacement measurements.To solve these problems,in this paper,first,a theoretical model of the phase variation of a singleparticle SMI signal burst is demonstrated in detail.The relationship between the phase variation and the particle size is investigated,which predicts that phase observation could be another alternative for particle detection.Second,combined with continuous wavelet transform and Hilbert transform,a novel phase-unwrapping algorithm is proposed.This algorithm can implement not only efficient individual burst extraction from the noisy raw signal,but also precise phase calculation for particle sizing.The measurement shows good accuracy over a range from 100 nm to 6μm with our algorithm,proving that our algorithm enables a simple and reliable quantitative particle characteristics retrieval and analysis methodology for microscale particle detection in biomedical or laser manufacturing fields.
基金National Natural Science Foundation of China(11704183,11974188,11704184,51701176)Double Innovation Project of Jiangsu Province(CZ106SC19010)NUPTSF(NY219015)。
文摘Strong coupling(SC) between two resonant plasmon modes can result in the formation of new hybrid modes exhibiting Rabi splitting with strong energy exchange at the nanoscale. However, normal Rabi splitting is often limited to ~50–320 me V due to the short lifetime of the plasmon mode. Here, we theoretically demonstrate a record Rabi splitting energy as large as 805 me V arising from the SC between the high-Q plasmonic whispering gallery mode and high-Q cavity plasmon resonance supported by a spherical hyperbolic metamaterial cavity,which consists of a dielectric nanosphere core wrapped in 7 alternating layers of silver/dielectric materials.In addition, the new hybrid modes formed by the SC are shown to exhibit an extralong lifetime of up to 71.9–81.6 fs, with the large electric field intensity enhancement at both the dielectric core and the dielectric layers. More importantly, the spectral ranges of SC can be tuned across an ultrabroad range from the visible to the near-IR by simply changing the dielectric core size. These findings may have potential applications in bright single-photon sources.
基金supported by the National Key R&D Program of China(No.2018YFB1801001)the National Natural Science Foundation of China(No.62222505)the Guangdong Introducing Innovative Entrepreneurial Teams of the Pearl River Talent Recruitment Program(Nos.2019ZT08X340 and 2021ZT09X044).
文摘Realizing high-fidelity optical information transmission through a scattering medium is of vital importance in both science and applications,such as short-range fiber communication and optical encryption.Theoretically,an input wavefront can be reconstructed by inverting the transmission matrix of the scattering medium.However,this deterministic method for retrieving light field information encoded in the wavefront has not yet been experimentally demonstrated.Herein,we demonstrate light field information transmission through different scattering media with near-unity fidelity.Multi-dimensional optical information can be delivered through either a multimode fiber or a ground glass without relying on any averaging or approximation,where their Pearson correlation coefficients can be up to 99%.
基金supported by the National Key R&D Program of China(No.2018YFB1800903)the National Natural Science Foundation of China(No.62005052)+2 种基金the Guangdong Introducing Innovative and Entrepreneurial Teams of“The Pearl River Talent Recruitment Program”(No.2019ZT08X340)the Guangdong Provincial Key Laboratory of Photonics Information Technology(No.2020B121201011)the Key Laboratory of All Optical Network and Advanced Telecommunication Network,Ministry of Education(Beijing Jiaotong University)(No.AON2019002)。
文摘We proposed and experimentally demonstrated an all-fiber sensor for measuring bend with high sensitivity based on a ring core fiber(RCF)modal interferometer.The sensor was fabricated by splicing a segment of RCF between two pieces of multimode fiber(MMF)and single-mode fiber(SMF)at the ends of the MMF as lead-in and lead-out.Due to the first segment of the MMF,the transmitted light is coupled into the ring core,silica center,and cladding of the RCF,exciting multiple modes in the RCF.By the modal interferences in the structure,bending sensing can be realized by interrogating the intensity of the interference dip.Experimental results show a high bending sensitivity of-25.63 dB/m^(-1)in the range of 1.0954 m^(-1)to1.4696 m^(-1).In addition,the advantages of the bend sensor,such as small size,low temperature sensitivity,and simple fabrication process,can be used for curvature measurement in building health monitoring.
