Paper-based devices have attracted extensive attention due to the growing demand for disposable flexible electronics.Herein,we integrate semiconducting devices on cellulose paper substrate through a simple abrasion te...Paper-based devices have attracted extensive attention due to the growing demand for disposable flexible electronics.Herein,we integrate semiconducting devices on cellulose paper substrate through a simple abrasion technique that yields high-performance photodetectors.A solvent-free WS_(2) film deposited on paper favors an effective electron-hole separation and hampers recombination.The as-prepared paper-based WS2 photodetectors exhibit a sensitive photoresponse over a wide spectral range spanning from ultraviolet(365 nm)to near-infrared(940 nm).Their responsivity value reaches up to~270 mA W^(−1) at 35 V under a power density of 35 mW cm^(−2).A high performance photodetector was achieved by controlling the environmental exposure as the ambient oxygen molecules were found to decrease the photoresponse and stability of the WS_(2) photodetector.Furthermore,we have built a spectrometer using such a paperbased WS_(2) device as the photodetecting component to illustrate its potential application.The present work could promote the development of cost-effective disposable photodetection devices.展开更多
The conversion-efficiency for second-harmonic(SH)in optical fibers is significantly limited by extremely weak second-order nonlinearity of fused silica,and pulse pump lasers with high peak power are widely employed.He...The conversion-efficiency for second-harmonic(SH)in optical fibers is significantly limited by extremely weak second-order nonlinearity of fused silica,and pulse pump lasers with high peak power are widely employed.Here,we propose a simple strategy to efficiently realize the broadband and continuous wave(CW)pumped SH,by transferring a crystalline GaSe coating onto a microfiber with phase-matching diameter.In the experiment,high efficiency up to 0.08%W-1mm-1 is reached for a C-band pump laser.The high enough efficiency not only guarantees SH at a single frequency pumped by a CW laser,but also multi-frequencies mixing supported by three CW light sources.Moreover,broadband SH spectrum is also achieved under the pump of a superluminescent light-emitting diode source with a 79.3 nm bandwidth.The proposed scheme provides a beneficial method to the enhancement of various nonlinear parameter processes,development of quasi-monochromatic or broadband CW light sources at new wavelength regions.展开更多
Flat optical elements have attracted enormous attentions and act as promising candidates for the next generation of optical components.As one of the most outstanding representatives,liquid crystal(LC)has been widely a...Flat optical elements have attracted enormous attentions and act as promising candidates for the next generation of optical components.As one of the most outstanding representatives,liquid crystal(LC)has been widely applied in flat panel display industries and inspires the wavefront modulation with the development of LC alignment techniques.However,most LC elements perform only one type of optical manipulation and are difficult to realize the multifunctionality and light integration.Here,flat multifunctional liquid crystal elements(FMLCEs),merely composed of anisotropic LC molecules with space-variant orientations,are presented for multichannel information manipulation by means of polarization,space and wavelength multiplexing.Specifically,benefiting from the unique light response with the change of the incident polarization,observation plane,and working wavelength,a series of FMLCEs are demonstrated to achieve distinct near-and far-field display functions.The proposed strategy takes full advantage of basic optical parameters as the decrypted keys to improve the information capacity and security,and we expect it to find potential applications in information encryption,optical anti-counterfeiting,virtual/augmented reality,etc.展开更多
The spin Hall effect of a light beam is essentially a product of circular birefringence but is rarely demonstrated.Here,we provide a scheme for initiating off-axis circular birefringence based on the spin-dependent wa...The spin Hall effect of a light beam is essentially a product of circular birefringence but is rarely demonstrated.Here,we provide a scheme for initiating off-axis circular birefringence based on the spin-dependent wave vector bifurcation of Bessel beams via a single liquid crystal Pancharatnam–Berry phase element.The tilted Bessel beam shows a detectable photonic spin Hall effect.By introducing the nonlinear propagation trajectories,the spin Hall effect is greatly enhanced.More surprisingly,the two spin states exactly propagate along the scaled trajectories,enabling flexible control of the spin separation.This phenomenon is also applicable to other Bessel-like beams with nonlinear trajectories,which have been already reported.展开更多
Graphene and related two-dimensional materials have attracted great research interests due to prominently optical and electrical properties and flexibility in integration with versatile photonic structures.Here,we rep...Graphene and related two-dimensional materials have attracted great research interests due to prominently optical and electrical properties and flexibility in integration with versatile photonic structures.Here,we report an in-fiber photoelec-tric device by wrapping a few-layer graphene and bonding a pair of electrodes onto a tilted fiber Bragg grating(TFBG)for photoelectric and electric-induced thermo-optic conversions.The transmitted spectrum from this device consists of a dense comb of narrowband resonances that provides an observable window to sense the photocurrent and the electrical injection in the graphene layer.The device has a wavelength-sensitive photoresponse with responsivity up to 11.4 A/W,allowing the spectrum analysis by real-time monitoring of photocurrent evolution.Based on the thermal-optic effect of electrical injection,the graphene layer is energized to produce a global red-shift of the transmission spectrum of the TF-BG,with a high sensitivity approaching 2.167×10^(4)nm/A^(2).The in-fiber photoelectric device,therefore as a powerful tool,could be widely available as off-the-shelf product for photodetection,spectrometer and current sensor.展开更多
The suppression of polarization cross talk in lead zirconate titanate phase modulators as a key error source has been challenging for open-loop fiber optic gyroscopes(FOGs).We developed a polarization-diversity optica...The suppression of polarization cross talk in lead zirconate titanate phase modulators as a key error source has been challenging for open-loop fiber optic gyroscopes(FOGs).We developed a polarization-diversity optical frequency domain reflectometry(OFDR)to measure the distributed modulation polarization error in the modulator.The error contributes 8×10^(−6) rad to FOG’s bias instability.Using a UV-fabricated in-fiberλ/4 wave plate and polarization-mode converter with fiber taper technology,the modulation error has been suppressed by 15 dB in assembled FOGs.This approach reduced error with temperature from 25°/h to 0.7°/h,meeting the requirements of control-level gyroscopes with bias errors less than 1°/h.展开更多
Two-dimensional(2D)materials that combine ferromagnetic,semiconductor,and piezoelectric properties hold significant potential for both fundamental research and spin electronic devices.However,the majority of reported ...Two-dimensional(2D)materials that combine ferromagnetic,semiconductor,and piezoelectric properties hold significant potential for both fundamental research and spin electronic devices.However,the majority of reported 2D ferromagnetic-semiconductor-piezoelectric materials rely on d-electron systems,which limits their practical applications due to a Curie temperature lower than room temperature(RT).Here,we report a high-crystallinity carbon nitride(CCN)material based on sp-electrons using a chemical vapor deposition strategy.CCN exhibits a band gap of 1.8 eV and has been confirmed to possess substantial in-plane and out-of-plane piezoelectricity.Moreover,we acquired clear evidences of ferromagnetic behavior at room temperature.Extensive structural characterizations combined with theoretical calculations reveal that incorporating structural oxygen into the highly ordered heptazine structure causes partial substitution of nitrogen sites,which is primarily responsible for generating room-temperature ferromagnetism and piezoelectricity.As a result,the strain in wrinkles can effectively modulate the domain behavior and piezoelectric potential at room temperature.The addition of RT ferromagnetic-semiconductor-piezoelectric material based on sp-electrons to the family of two-dimensional materials opens up numerous possibilities for novel applications in fundamental research and spin electronic devices.展开更多
Highly integrated optoelectronic and photonic systems underpin the development of next-generation advanced optical and quantum communication technologies,which require compact,multiwavelength laser sources at the tele...Highly integrated optoelectronic and photonic systems underpin the development of next-generation advanced optical and quantum communication technologies,which require compact,multiwavelength laser sources at the telecom band.Here,we report on-substrate vertical emitting lasing from ordered InGaAs/InP multi-quantum well core–shell nanowire array epitaxially grown on InP substrate by selective area epitaxy.To reduce optical loss and tailor the cavity mode,a new nanowire facet engineering approach has been developed to achieve controlled quantum well nanowire dimensions with uniform morphology and high crystal quality.Owing to the strong quantum confinement effect of InGaAs quantum wells and the successful formation of a vertical Fabry–Pérot cavity between the top nanowire facet and bottom nanowire/SiO_(2) mask interface,stimulated emissions of the EH11a/b mode from single vertical nanowires from an on-substrate nanowire array have been demonstrated with a lasing threshold of~28.2μJ cm^(−2) per pulse and a high characteristic temperature of~128 K.By fine-tuning the In composition of the quantum wells,room temperature,single-mode lasing is achieved in the vertical direction across a broad near-infrared spectral range,spanning from 940 nm to the telecommunication O and C bands.Our research indicates that through a carefully designed facet engineering strategy,highly ordered,uniform nanowire arrays with precise dimension control can be achieved to simultaneously deliver thousands of nanolasers with multiple wavelengths on the same substrate,paving a promising and scalable pathway towards future advanced optoelectronic and photonic systems.展开更多
We numerically demonstrate that the tight focusing of Bessel beams can generate focal fields with an ultra-long depth of focus(DOF).The ultra-long focal field can be controlled by appropriately regulating the order of...We numerically demonstrate that the tight focusing of Bessel beams can generate focal fields with an ultra-long depth of focus(DOF).The ultra-long focal field can be controlled by appropriately regulating the order of the Bessel function and the polarization.An optical needle and an optical dark channel with nearly 100λDOF are generated.The optical needle has a DOF of~104.9λand a super-diffraction-limited focal spot with the size of 0.19λ^(2).The dark channel has a full-width at halfmaximum of~0.346λand a DOF of~103.8λ.Furthermore,the oscillating focal field with an ultra-long DOF can be also generated by merely changing the order of the input Bessel beam.Our results are expected to contribute to potential applications in optical tweezers,atom guidance and capture,and laser processing.展开更多
We have observed various polarization domains and a giant self-mode-locked pulse in a 130 m long erbium-doped fiber laser without any mode-locking devices.By adjusting the intracavity polarization controller,we invest...We have observed various polarization domains and a giant self-mode-locked pulse in a 130 m long erbium-doped fiber laser without any mode-locking devices.By adjusting the intracavity polarization controller,we investigated the evolution process of the polarization domain with the varying cavity birefringence.When the birefringence was close to zero,the polarization domains split into multidomains,and finally a giant self-mode-locked pulse formed for the first time.We analyzed that the generation of the self-mode-locked pulse was related to the multiple subdomains ascribed to the strong coherent cross coupling between the orthogonal polarization light components in the long fiber cavity.展开更多
Based on the transverse-longitudinal mapping of Bessel beams,we propose a simple method to construct a self-similar Bessel-like beam whose transverse profile maintains a stretched form during propagation.Specifically,...Based on the transverse-longitudinal mapping of Bessel beams,we propose a simple method to construct a self-similar Bessel-like beam whose transverse profile maintains a stretched form during propagation.Specifically,the propagatingvariant width of this beam can be flexibly predesigned.We experimentally demonstrate three types of self-similar Bessellike beams whose width variations are linear,piecewise,and period functions of propagation distance,respectively.The experimental results match well with the theoretical predictions.We also demonstrate that our approach enables the generation of self-similar higher-order vortex Bessel-like beams.展开更多
The miniaturization of spectrometers has received much attention in recent years.The rapid development of metasurfaces has provided a new avenue for creating more compact and lightweight spectrometers.However,most met...The miniaturization of spectrometers has received much attention in recent years.The rapid development of metasurfaces has provided a new avenue for creating more compact and lightweight spectrometers.However,most metasurface-based spectrometers operate in the visible light region,with much less research on near-infrared wavelengths.This is possibly caused by the lack of effective metasurface filters for the near-infrared light.We design and fabricate a polarizationinsensitive amorphous silicon metasurface that exhibits unique transmission spectra in parts of the visible and nearinfrared wavelengths.By passing the light to be measured through a metasurface filter array and measuring the transmitted power,we achieve the precise reconstruction of unknown spectra in the visible and near-infrared range(450-950 nm)using an algorithm matched to the filter model.Our approach is a step towards miniaturized spectrometers within the visible-to-near-infrared range based on metasurface filter arrays.展开更多
We demonstrate an intracavity self-synchronized multi-color Q-switched fiber laser using a parallel-integrated fiber Bragg grating(PI-FBG), fabricated by a femtosecond laser with a point-by-point parallel inscription ...We demonstrate an intracavity self-synchronized multi-color Q-switched fiber laser using a parallel-integrated fiber Bragg grating(PI-FBG), fabricated by a femtosecond laser with a point-by-point parallel inscription method. The multi-color Q-switched pulses can be always self-synchronized when the group delay differences between neighboring spectra range from-3.4 to 3.4 ps.The starting and evolution dynamics indicate that the saturable absorption effect of the carbon nanotube plays a dual role: synchronously triggering the startup of the pulse at successive colors by active Q-switching and spontaneously compensating to some extent the temporal walk-off of the multi-color pulses through the cross saturable absorption modulation. This work unveils the intracavity self-synchronization mechanism of the multi-color Q-switched pulses and also demonstrates the potential of PI-FBGs for the customizable generation of the synchronized multi-color pulse in a single cavity.展开更多
Surface plasmon resonance microscopy(SPRM)has been massively applied for near-field optical measurement,sensing,and imaging because of its high detection sensitivity,nondestructive,noninvasive,wide-field,and label-fre...Surface plasmon resonance microscopy(SPRM)has been massively applied for near-field optical measurement,sensing,and imaging because of its high detection sensitivity,nondestructive,noninvasive,wide-field,and label-free imaging capabilities.However,the transverse propagation characteristic of the surface plasmon wave generated during surface plasmon resonance(SPR)leads to notable“tail”patterns in the SPR image,which severely deteriorates the image quality.Here,we propose an incidence angle scanning method in SPRM to obtain a resonance angle image with exceptional contrast that significantly mitigates the adverse effects of“tail”patterns.The resonance angle image provides the complete morphology of the analyzed samples and enables two-dimensional quantification,which is incapable in conventional SPRM.The effectiveness of the method was experimentally verified using photoresist square samples with different sizes and two-dimensional materials with various geometric shapes.The edges of samples were fully reconstructed and a maximum fivefold increase in the image contrast has been achieved.Our method offers a convenient way to enhance the SPRM imaging capabilities with low cost and stable performance,which greatly expands the applications of SPRM in label-free detection,imaging,and quantification.展开更多
Pancharatnam–Berry (PB) phase has become an effective tool to realize the photonic spin Hall effect (PSHE) in recent years, due to its capacity of enhancing the spin-orbit interaction. Various forms of PSHEs have bee...Pancharatnam–Berry (PB) phase has become an effective tool to realize the photonic spin Hall effect (PSHE) in recent years, due to its capacity of enhancing the spin-orbit interaction. Various forms of PSHEs have been proposed by tailoring the PB phase of light, however, the propagation trajectory control of the separated spin states has not been reported. In this paper, we realize the oscillated spin-dependent separation by using the well-designed PB phase optical elements based on the transverse-to-longitudinal mapping of Bessel beams. Two typical oscillated PSHEs, i.e., the spin states are circulated and reversed periodically, are experimentally demonstrated with two PB phase elements fabricated with liquid crystal. The displacements and periods of these oscillations can be controlled by changing the transverse vector of the input Bessel beam. The proposed method offers a new degree of freedom to manipulate the spin-dependent separation, and provides technical supports for the application in spin photonics.展开更多
Two-dimensional materials are attractive for constructing high-performance photonic chip-integrated photodetectors because of their remarkable electronic and optical properties and dangling-bond-free surfaces.However,...Two-dimensional materials are attractive for constructing high-performance photonic chip-integrated photodetectors because of their remarkable electronic and optical properties and dangling-bond-free surfaces.However,the reported chip-integrated two-dimensional material photodetectors were mainly implemented with the configuration of metalsemiconductor-metal,suffering from high dark currents and low responsivities at high operation speed.Here,we report a van der Waals PN heterojunction photodetector,composed of p-type black phosphorous and n-type molybdenum telluride,integrated on a silicon nitride waveguide.The built-in electric field of the PN heterojunction significantly suppresses the dark current and improves the responsivity.Under a bias of 1 V pointing from n-type molybdenum telluride to p-type black phosphorous,the dark current is lower than 7 nA,which is more than two orders of magnitude lower than those reported in other waveguide-integrated black phosphorus photodetectors.An intrinsic responsivity up to 577 mA W^(−1) is obtained.Remarkably,the van der Waals PN heterojunction is tunable by the electrostatic doping to further engineer its rectification and improve the photodetection,enabling an increased responsivity of 709 mA W^(−1).Besides,the heterojunction photodetector exhibits a response bandwidth of~1.0 GHz and a uniform photodetection over a wide spectral range,as experimentally measured from 1500 to 1630 nm.The demonstrated chip-integrated van der Waals PN heterojunction photodetector with low dark current,high responsivity and fast response has great potentials to develop high-performance on-chip photodetectors for various photonic integrated circuits based on silicon,lithium niobate,polymer,etc.展开更多
Digital holography possesses the advantages of wide-field,non-contact,precise,and dynamic measurements for the complex amplitude of object waves.Today,digital holography and its derivatives have been widely applied in...Digital holography possesses the advantages of wide-field,non-contact,precise,and dynamic measurements for the complex amplitude of object waves.Today,digital holography and its derivatives have been widely applied in interferometric measurements,three-dimensional imaging,and quantitative phase imaging,demonstrating significant potential in the material science,industry,and biomedical fields,among others.However,in conventional off-axis holographic experimental setups,the object and reference beams propagate in separated paths,resulting in low temporal stability and measurement sensitivity.By designing common-path configurations where the two interference beams share the same or similar paths,environmental disturbance to the two beams can be effectively compensated.Therefore,the temporal stability of the experimental setups for hologram recording can be significantly improved for time-lapsing measurements.In this review,we categorise the common-path models as lateral shearing,point diffraction,and other types based on the different approaches to generate the reference beam.Benefiting from compact features,common-path digital holography is extremely promising for the manufacture of highly stable optical measurement and imaging instruments in the future.展开更多
Artificial resonant metamaterial with subwavelength localized filed is promising for advanced nonlinear photonic applications.In this article,we demonstrate enhanced nonlinear frequency-agile response and hysteresis t...Artificial resonant metamaterial with subwavelength localized filed is promising for advanced nonlinear photonic applications.In this article,we demonstrate enhanced nonlinear frequency-agile response and hysteresis tunability in a Fano-resonant hybrid metamaterial.A ceramic cuboid is electromagnetically coupled with metal cut-wire structure to excite the high-Q Fano-resonant mode in the dielectric/metal hybrid metamaterial.It is found that the significant nonlinear response of the ceramic cuboid can be employed for realization of tunable metamaterials by exciting its magnetic mode,and the trapped mode with an asymmetric Fano-like resonance is beneficial to achieve notable nonlinear modulation on the scattering spectrum.The nonlinear tunability of both the ceramic structure and the ceramic/metal hybrid metamaterial is promising to extend the operation band of metamaterials,providing possibility in practical applications with enhanced light-matter interactions.展开更多
Second harmonic generation(SHG)in optical materials serves as important techniques for laser source generations in awkward spectral ranges,physical identities of materials in crystalline symmetry and interfacial confi...Second harmonic generation(SHG)in optical materials serves as important techniques for laser source generations in awkward spectral ranges,physical identities of materials in crystalline symmetry and interfacial configuration.Here,we present a comprehensive review on SHGs in nanowires(NWs),which have been recognized as an important element in constructing photonic and optoelectronic devices with compact footprint and high quantum yield.Relying on NW’s one-dimensional geometry,its SHG could be employed as a sophisticated spectroscopy to determine the crystal phase and orientation,as well as the internal strain.The enhancements of SHG efficiency in NWs are discussed then,which were realized by hybrid integrating them with two-dimensional materials,nanophotonic and plasmonic structures.Finally,the potential applications of NW SHGs are concluded,including the areas of optical correlators and constructions of on-chip nano-laser sources.展开更多
Noble metallic nanostructures with strong electric near-field enhancement can significantly improve nanoscale light-matter interactions and are critical for high-sensitivity surface-enhanced Raman spectroscopy[SERS].H...Noble metallic nanostructures with strong electric near-field enhancement can significantly improve nanoscale light-matter interactions and are critical for high-sensitivity surface-enhanced Raman spectroscopy[SERS].Here,we use an azimuthal vector beam[AVB]to illuminate the plasmonic tips circular cluster[PTCC]array to enhance the electric near-field intensity of the PTCC array,and then use it to improve SERS sensitivity.The PTCC array was prepared based on the self-assembled and inductive coupled plasmon[ICP]etching methods.The calculation results show that,compared with the linearly polarized beam[LPB]and radial vector beam excitations,the AVB excitation can obtain stronger electric near-field enhancement due to the strong resonant responses formed in the nanogap between adjacent plasmonic tips.Subsequently,our experimental results proved that AVB excitation increased SERS sensitivity to 10-13mol/L,which is two orders of magnitude higher than that of LPB excitation.Meanwhile,the PTCC array had excellent uniformity with the Raman enhancement factor calculated to be~2.4×10^[8].This kind of vector light field enhancing Raman spectroscopy may be applied in the field of sensing technologies,such as the trace amount detection.展开更多
基金Felix Carrascoso (ICMM-CSIC) for support with the metal evaporationfunding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement n°755655,ERC-StG 2017 project2D-TOPSENSE)+5 种基金the Ministry of Science and Innovation (Spain) through the project PID2020-115566RB-I00support from the National Natural Science Foundation of China under grant No.61704129 and No.62011530438the Key Research and Development Program of Shaanxi (Program No.2021KW-02)Fundamental Research Funds for the Central Universities (JB211409)the grant from China Scholarship Council (CSC) under No.201908610178the support from European Union’s Horizon 2020 research and innovation program under the grant agreement 956813 (2Exciting)。
文摘Paper-based devices have attracted extensive attention due to the growing demand for disposable flexible electronics.Herein,we integrate semiconducting devices on cellulose paper substrate through a simple abrasion technique that yields high-performance photodetectors.A solvent-free WS_(2) film deposited on paper favors an effective electron-hole separation and hampers recombination.The as-prepared paper-based WS2 photodetectors exhibit a sensitive photoresponse over a wide spectral range spanning from ultraviolet(365 nm)to near-infrared(940 nm).Their responsivity value reaches up to~270 mA W^(−1) at 35 V under a power density of 35 mW cm^(−2).A high performance photodetector was achieved by controlling the environmental exposure as the ambient oxygen molecules were found to decrease the photoresponse and stability of the WS_(2) photodetector.Furthermore,we have built a spectrometer using such a paperbased WS_(2) device as the photodetecting component to illustrate its potential application.The present work could promote the development of cost-effective disposable photodetection devices.
基金supports from National Natural Science Foundation of China(No.61975166,11634010)Key Research and Development Program(No.2017YFA0303800).
文摘The conversion-efficiency for second-harmonic(SH)in optical fibers is significantly limited by extremely weak second-order nonlinearity of fused silica,and pulse pump lasers with high peak power are widely employed.Here,we propose a simple strategy to efficiently realize the broadband and continuous wave(CW)pumped SH,by transferring a crystalline GaSe coating onto a microfiber with phase-matching diameter.In the experiment,high efficiency up to 0.08%W-1mm-1 is reached for a C-band pump laser.The high enough efficiency not only guarantees SH at a single frequency pumped by a CW laser,but also multi-frequencies mixing supported by three CW light sources.Moreover,broadband SH spectrum is also achieved under the pump of a superluminescent light-emitting diode source with a 79.3 nm bandwidth.The proposed scheme provides a beneficial method to the enhancement of various nonlinear parameter processes,development of quasi-monochromatic or broadband CW light sources at new wavelength regions.
基金the supports from the National Natural Science Foundation of China (61905073, 61835004, 62134001, 61905031, 62105263, 62275077)Fundamental Research Fund for the Central Universities (531118010189, 310202011qd002)+1 种基金the support from Xi’an Science and Technology Association Youth Talent Support Project (095920211306)the Postdoctoral Innovation Talent Support Program of China (BX20220388)
文摘Flat optical elements have attracted enormous attentions and act as promising candidates for the next generation of optical components.As one of the most outstanding representatives,liquid crystal(LC)has been widely applied in flat panel display industries and inspires the wavefront modulation with the development of LC alignment techniques.However,most LC elements perform only one type of optical manipulation and are difficult to realize the multifunctionality and light integration.Here,flat multifunctional liquid crystal elements(FMLCEs),merely composed of anisotropic LC molecules with space-variant orientations,are presented for multichannel information manipulation by means of polarization,space and wavelength multiplexing.Specifically,benefiting from the unique light response with the change of the incident polarization,observation plane,and working wavelength,a series of FMLCEs are demonstrated to achieve distinct near-and far-field display functions.The proposed strategy takes full advantage of basic optical parameters as the decrypted keys to improve the information capacity and security,and we expect it to find potential applications in information encryption,optical anti-counterfeiting,virtual/augmented reality,etc.
基金National Key Research and Development Program of China(2022YFA1404800)National Natural Science Foundation of China(12074312,12174309,12074313)Fundamental Research Funds for the Central Universities(3102019JC008)。
文摘The spin Hall effect of a light beam is essentially a product of circular birefringence but is rarely demonstrated.Here,we provide a scheme for initiating off-axis circular birefringence based on the spin-dependent wave vector bifurcation of Bessel beams via a single liquid crystal Pancharatnam–Berry phase element.The tilted Bessel beam shows a detectable photonic spin Hall effect.By introducing the nonlinear propagation trajectories,the spin Hall effect is greatly enhanced.More surprisingly,the two spin states exactly propagate along the scaled trajectories,enabling flexible control of the spin separation.This phenomenon is also applicable to other Bessel-like beams with nonlinear trajectories,which have been already reported.
基金We are grateful for financial supports from National Natural Science Foundation of China(Grant No.61975166)Key Research and Development Program(Grant No.2022YFA1404800).
文摘Graphene and related two-dimensional materials have attracted great research interests due to prominently optical and electrical properties and flexibility in integration with versatile photonic structures.Here,we report an in-fiber photoelec-tric device by wrapping a few-layer graphene and bonding a pair of electrodes onto a tilted fiber Bragg grating(TFBG)for photoelectric and electric-induced thermo-optic conversions.The transmitted spectrum from this device consists of a dense comb of narrowband resonances that provides an observable window to sense the photocurrent and the electrical injection in the graphene layer.The device has a wavelength-sensitive photoresponse with responsivity up to 11.4 A/W,allowing the spectrum analysis by real-time monitoring of photocurrent evolution.Based on the thermal-optic effect of electrical injection,the graphene layer is energized to produce a global red-shift of the transmission spectrum of the TF-BG,with a high sensitivity approaching 2.167×10^(4)nm/A^(2).The in-fiber photoelectric device,therefore as a powerful tool,could be widely available as off-the-shelf product for photodetection,spectrometer and current sensor.
基金supported by the National Natural Science Foundation of China(Nos.61975166,62322510,and 62375223).
文摘The suppression of polarization cross talk in lead zirconate titanate phase modulators as a key error source has been challenging for open-loop fiber optic gyroscopes(FOGs).We developed a polarization-diversity optical frequency domain reflectometry(OFDR)to measure the distributed modulation polarization error in the modulator.The error contributes 8×10^(−6) rad to FOG’s bias instability.Using a UV-fabricated in-fiberλ/4 wave plate and polarization-mode converter with fiber taper technology,the modulation error has been suppressed by 15 dB in assembled FOGs.This approach reduced error with temperature from 25°/h to 0.7°/h,meeting the requirements of control-level gyroscopes with bias errors less than 1°/h.
基金the National Key R&D Program of China(No.2022ZD0119002)the National Natural Science Foundation of China(Nos.62025402,62090033,91964202,92064003,92264202,62293522,12104352,and 12204294)+3 种基金the Major Program of Zhejiang Natural Science Foundation(No.DT23F0402)the Fundamental Research Funds for the Central Universities(Nos.QTZX23040 and QTZX23079)the China National Postdoctoral Programme for Innovative Talents(No.BX20230281)the Natural Science Basic Research Program of Shaanxi(No.2023JC-XJ-01).
文摘Two-dimensional(2D)materials that combine ferromagnetic,semiconductor,and piezoelectric properties hold significant potential for both fundamental research and spin electronic devices.However,the majority of reported 2D ferromagnetic-semiconductor-piezoelectric materials rely on d-electron systems,which limits their practical applications due to a Curie temperature lower than room temperature(RT).Here,we report a high-crystallinity carbon nitride(CCN)material based on sp-electrons using a chemical vapor deposition strategy.CCN exhibits a band gap of 1.8 eV and has been confirmed to possess substantial in-plane and out-of-plane piezoelectricity.Moreover,we acquired clear evidences of ferromagnetic behavior at room temperature.Extensive structural characterizations combined with theoretical calculations reveal that incorporating structural oxygen into the highly ordered heptazine structure causes partial substitution of nitrogen sites,which is primarily responsible for generating room-temperature ferromagnetism and piezoelectricity.As a result,the strain in wrinkles can effectively modulate the domain behavior and piezoelectric potential at room temperature.The addition of RT ferromagnetic-semiconductor-piezoelectric material based on sp-electrons to the family of two-dimensional materials opens up numerous possibilities for novel applications in fundamental research and spin electronic devices.
基金supported by the Key Research and Development Program(2022YFA1404800)the National Natural Science Foundation of China(62375226,62375225,12374359,62105267)+1 种基金the Fundamental Research Funds for the Central Universities(23GH02023)the Analytical&Testing Center of Northwestern Polytechnical University and the Australian Research Council.The Australian National Fabrication Facility ACT Node is acknowledged for access to the epitaxial growth facilities.
文摘Highly integrated optoelectronic and photonic systems underpin the development of next-generation advanced optical and quantum communication technologies,which require compact,multiwavelength laser sources at the telecom band.Here,we report on-substrate vertical emitting lasing from ordered InGaAs/InP multi-quantum well core–shell nanowire array epitaxially grown on InP substrate by selective area epitaxy.To reduce optical loss and tailor the cavity mode,a new nanowire facet engineering approach has been developed to achieve controlled quantum well nanowire dimensions with uniform morphology and high crystal quality.Owing to the strong quantum confinement effect of InGaAs quantum wells and the successful formation of a vertical Fabry–Pérot cavity between the top nanowire facet and bottom nanowire/SiO_(2) mask interface,stimulated emissions of the EH11a/b mode from single vertical nanowires from an on-substrate nanowire array have been demonstrated with a lasing threshold of~28.2μJ cm^(−2) per pulse and a high characteristic temperature of~128 K.By fine-tuning the In composition of the quantum wells,room temperature,single-mode lasing is achieved in the vertical direction across a broad near-infrared spectral range,spanning from 940 nm to the telecommunication O and C bands.Our research indicates that through a carefully designed facet engineering strategy,highly ordered,uniform nanowire arrays with precise dimension control can be achieved to simultaneously deliver thousands of nanolasers with multiple wavelengths on the same substrate,paving a promising and scalable pathway towards future advanced optoelectronic and photonic systems.
基金supported by the National Key Research and Development Program of China(No.2022YFA1404800)National Natural Science Foundation of China(NSFC)(Nos.12074312,11634010,12074313,and 12174309)+1 种基金Fundamental Research Funds for the Central Universities(No.3102019JC008)Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(No.CX2021115)。
文摘We numerically demonstrate that the tight focusing of Bessel beams can generate focal fields with an ultra-long depth of focus(DOF).The ultra-long focal field can be controlled by appropriately regulating the order of the Bessel function and the polarization.An optical needle and an optical dark channel with nearly 100λDOF are generated.The optical needle has a DOF of~104.9λand a super-diffraction-limited focal spot with the size of 0.19λ^(2).The dark channel has a full-width at halfmaximum of~0.346λand a DOF of~103.8λ.Furthermore,the oscillating focal field with an ultra-long DOF can be also generated by merely changing the order of the input Bessel beam.Our results are expected to contribute to potential applications in optical tweezers,atom guidance and capture,and laser processing.
基金supported by the National Key Research and Development Program of China(No.2018YFE0117400)National Natural Science Foundation of China(No.62275093)China Postdoctoral Science Foundation(No.2018M642823)。
文摘We have observed various polarization domains and a giant self-mode-locked pulse in a 130 m long erbium-doped fiber laser without any mode-locking devices.By adjusting the intracavity polarization controller,we investigated the evolution process of the polarization domain with the varying cavity birefringence.When the birefringence was close to zero,the polarization domains split into multidomains,and finally a giant self-mode-locked pulse formed for the first time.We analyzed that the generation of the self-mode-locked pulse was related to the multiple subdomains ascribed to the strong coherent cross coupling between the orthogonal polarization light components in the long fiber cavity.
基金supported by the National Key Research and Development Program of China(No.2022YFA1404800)the National Natural Science Foundation of China(Nos.12074312,12174309,12074313,and 62175200)the Fundamental Research Funds for the Central Universities(No.3102019JC008)。
文摘Based on the transverse-longitudinal mapping of Bessel beams,we propose a simple method to construct a self-similar Bessel-like beam whose transverse profile maintains a stretched form during propagation.Specifically,the propagatingvariant width of this beam can be flexibly predesigned.We experimentally demonstrate three types of self-similar Bessellike beams whose width variations are linear,piecewise,and period functions of propagation distance,respectively.The experimental results match well with the theoretical predictions.We also demonstrate that our approach enables the generation of self-similar higher-order vortex Bessel-like beams.
基金supported by the National Natural Science Foundation of China(No.62175200)the National Key Research and Development Program of China(No.2022YFA1404800).
文摘The miniaturization of spectrometers has received much attention in recent years.The rapid development of metasurfaces has provided a new avenue for creating more compact and lightweight spectrometers.However,most metasurface-based spectrometers operate in the visible light region,with much less research on near-infrared wavelengths.This is possibly caused by the lack of effective metasurface filters for the near-infrared light.We design and fabricate a polarizationinsensitive amorphous silicon metasurface that exhibits unique transmission spectra in parts of the visible and nearinfrared wavelengths.By passing the light to be measured through a metasurface filter array and measuring the transmitted power,we achieve the precise reconstruction of unknown spectra in the visible and near-infrared range(450-950 nm)using an algorithm matched to the filter model.Our approach is a step towards miniaturized spectrometers within the visible-to-near-infrared range based on metasurface filter arrays.
基金supported by the National Natural Science Foundation of China (No.12274344)the Natural Science Basic Research Program of Shaanxi (No.2023-JC-YB-563)the Guangdong Basic and Applied Basic Research Foundation (No.2023A1515011517)。
文摘We demonstrate an intracavity self-synchronized multi-color Q-switched fiber laser using a parallel-integrated fiber Bragg grating(PI-FBG), fabricated by a femtosecond laser with a point-by-point parallel inscription method. The multi-color Q-switched pulses can be always self-synchronized when the group delay differences between neighboring spectra range from-3.4 to 3.4 ps.The starting and evolution dynamics indicate that the saturable absorption effect of the carbon nanotube plays a dual role: synchronously triggering the startup of the pulse at successive colors by active Q-switching and spontaneously compensating to some extent the temporal walk-off of the multi-color pulses through the cross saturable absorption modulation. This work unveils the intracavity self-synchronization mechanism of the multi-color Q-switched pulses and also demonstrates the potential of PI-FBGs for the customizable generation of the synchronized multi-color pulse in a single cavity.
基金National Natural Science Foundation of China(61927810,62275219).
文摘Surface plasmon resonance microscopy(SPRM)has been massively applied for near-field optical measurement,sensing,and imaging because of its high detection sensitivity,nondestructive,noninvasive,wide-field,and label-free imaging capabilities.However,the transverse propagation characteristic of the surface plasmon wave generated during surface plasmon resonance(SPR)leads to notable“tail”patterns in the SPR image,which severely deteriorates the image quality.Here,we propose an incidence angle scanning method in SPRM to obtain a resonance angle image with exceptional contrast that significantly mitigates the adverse effects of“tail”patterns.The resonance angle image provides the complete morphology of the analyzed samples and enables two-dimensional quantification,which is incapable in conventional SPRM.The effectiveness of the method was experimentally verified using photoresist square samples with different sizes and two-dimensional materials with various geometric shapes.The edges of samples were fully reconstructed and a maximum fivefold increase in the image contrast has been achieved.Our method offers a convenient way to enhance the SPRM imaging capabilities with low cost and stable performance,which greatly expands the applications of SPRM in label-free detection,imaging,and quantification.
基金the National Key R&D Program of China(2017YFA0303800)the National Natural Science Foundations of China(NSFC)(12074312,11634010,12174309,12074313,11774289,91850118,and 11804277)+1 种基金Fundamental Research Funds for the Central Universities(3102019JC008)Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX202047).
文摘Pancharatnam–Berry (PB) phase has become an effective tool to realize the photonic spin Hall effect (PSHE) in recent years, due to its capacity of enhancing the spin-orbit interaction. Various forms of PSHEs have been proposed by tailoring the PB phase of light, however, the propagation trajectory control of the separated spin states has not been reported. In this paper, we realize the oscillated spin-dependent separation by using the well-designed PB phase optical elements based on the transverse-to-longitudinal mapping of Bessel beams. Two typical oscillated PSHEs, i.e., the spin states are circulated and reversed periodically, are experimentally demonstrated with two PB phase elements fabricated with liquid crystal. The displacements and periods of these oscillations can be controlled by changing the transverse vector of the input Bessel beam. The proposed method offers a new degree of freedom to manipulate the spin-dependent separation, and provides technical supports for the application in spin photonics.
基金supported by the National Key R&D Program of China(Grant Nos.2018YFA0307200 and 2017YFA0303800)the National Natural Science Foundation of China(Grant Nos.61905198,61775183,11634010,and 61675171)+1 种基金Key Research and Development Program in Shaanxi Province of China(Grant Nos.2017KJXX-12,2018JM1058,and 2018KW-009)the Fundamental Research Funds for the Central Universities(Grant Nos.3102017jc01001,3102018jcc034,and 3102017HQZZ022)。
文摘Two-dimensional materials are attractive for constructing high-performance photonic chip-integrated photodetectors because of their remarkable electronic and optical properties and dangling-bond-free surfaces.However,the reported chip-integrated two-dimensional material photodetectors were mainly implemented with the configuration of metalsemiconductor-metal,suffering from high dark currents and low responsivities at high operation speed.Here,we report a van der Waals PN heterojunction photodetector,composed of p-type black phosphorous and n-type molybdenum telluride,integrated on a silicon nitride waveguide.The built-in electric field of the PN heterojunction significantly suppresses the dark current and improves the responsivity.Under a bias of 1 V pointing from n-type molybdenum telluride to p-type black phosphorous,the dark current is lower than 7 nA,which is more than two orders of magnitude lower than those reported in other waveguide-integrated black phosphorus photodetectors.An intrinsic responsivity up to 577 mA W^(−1) is obtained.Remarkably,the van der Waals PN heterojunction is tunable by the electrostatic doping to further engineer its rectification and improve the photodetection,enabling an increased responsivity of 709 mA W^(−1).Besides,the heterojunction photodetector exhibits a response bandwidth of~1.0 GHz and a uniform photodetection over a wide spectral range,as experimentally measured from 1500 to 1630 nm.The demonstrated chip-integrated van der Waals PN heterojunction photodetector with low dark current,high responsivity and fast response has great potentials to develop high-performance on-chip photodetectors for various photonic integrated circuits based on silicon,lithium niobate,polymer,etc.
基金Support from the National Natural Science Foundation of China(NSFC)(61927810,62075183,62005219)Fundamental Research Funds for the Central Universities(310202011qd004)is acknowledged.
文摘Digital holography possesses the advantages of wide-field,non-contact,precise,and dynamic measurements for the complex amplitude of object waves.Today,digital holography and its derivatives have been widely applied in interferometric measurements,three-dimensional imaging,and quantitative phase imaging,demonstrating significant potential in the material science,industry,and biomedical fields,among others.However,in conventional off-axis holographic experimental setups,the object and reference beams propagate in separated paths,resulting in low temporal stability and measurement sensitivity.By designing common-path configurations where the two interference beams share the same or similar paths,environmental disturbance to the two beams can be effectively compensated.Therefore,the temporal stability of the experimental setups for hologram recording can be significantly improved for time-lapsing measurements.In this review,we categorise the common-path models as lateral shearing,point diffraction,and other types based on the different approaches to generate the reference beam.Benefiting from compact features,common-path digital holography is extremely promising for the manufacture of highly stable optical measurement and imaging instruments in the future.
基金support from the Natural Science Foundation of China(NSFC)(Grants nos.61771402,12074314,and 11674266)the Science,Technology and Innovation Commission of Shenzhen Municipality(JCYJ20170817162221169)+3 种基金the NPU AoXiang New Star program,the Shaanxi Province Postdoctoral Science Foundation(no.2018BSHEDZZ64)the Natural Science Basic Research Plan in Shaanxi Province of China(nos.2018JM6024 and 2020JM-145)the National Research Fund of Ukraine(grant 2020.02/0218)National Academy of Sciences of Ukraine.
文摘Artificial resonant metamaterial with subwavelength localized filed is promising for advanced nonlinear photonic applications.In this article,we demonstrate enhanced nonlinear frequency-agile response and hysteresis tunability in a Fano-resonant hybrid metamaterial.A ceramic cuboid is electromagnetically coupled with metal cut-wire structure to excite the high-Q Fano-resonant mode in the dielectric/metal hybrid metamaterial.It is found that the significant nonlinear response of the ceramic cuboid can be employed for realization of tunable metamaterials by exciting its magnetic mode,and the trapped mode with an asymmetric Fano-like resonance is beneficial to achieve notable nonlinear modulation on the scattering spectrum.The nonlinear tunability of both the ceramic structure and the ceramic/metal hybrid metamaterial is promising to extend the operation band of metamaterials,providing possibility in practical applications with enhanced light-matter interactions.
基金supported by the Key Research and Development Program(Grant No.2022YFA1404800)the National Natural Science Foundation of China(Grant Nos.62105267 and 62375225)+1 种基金the Shaanxi Fundamental Science Research Project for Mathematics and Physics(Grant No.22JSY004)Xi’an Science and Technology Plan Project(Grant No.2023JH-ZCGJ-0023)。
文摘Second harmonic generation(SHG)in optical materials serves as important techniques for laser source generations in awkward spectral ranges,physical identities of materials in crystalline symmetry and interfacial configuration.Here,we present a comprehensive review on SHGs in nanowires(NWs),which have been recognized as an important element in constructing photonic and optoelectronic devices with compact footprint and high quantum yield.Relying on NW’s one-dimensional geometry,its SHG could be employed as a sophisticated spectroscopy to determine the crystal phase and orientation,as well as the internal strain.The enhancements of SHG efficiency in NWs are discussed then,which were realized by hybrid integrating them with two-dimensional materials,nanophotonic and plasmonic structures.Finally,the potential applications of NW SHGs are concluded,including the areas of optical correlators and constructions of on-chip nano-laser sources.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.11974282 and 91950207)the Doctoral Dissertation Innovation Fund of Northwestern Polytechnical University(No.CX2021039)。
文摘Noble metallic nanostructures with strong electric near-field enhancement can significantly improve nanoscale light-matter interactions and are critical for high-sensitivity surface-enhanced Raman spectroscopy[SERS].Here,we use an azimuthal vector beam[AVB]to illuminate the plasmonic tips circular cluster[PTCC]array to enhance the electric near-field intensity of the PTCC array,and then use it to improve SERS sensitivity.The PTCC array was prepared based on the self-assembled and inductive coupled plasmon[ICP]etching methods.The calculation results show that,compared with the linearly polarized beam[LPB]and radial vector beam excitations,the AVB excitation can obtain stronger electric near-field enhancement due to the strong resonant responses formed in the nanogap between adjacent plasmonic tips.Subsequently,our experimental results proved that AVB excitation increased SERS sensitivity to 10-13mol/L,which is two orders of magnitude higher than that of LPB excitation.Meanwhile,the PTCC array had excellent uniformity with the Raman enhancement factor calculated to be~2.4×10^[8].This kind of vector light field enhancing Raman spectroscopy may be applied in the field of sensing technologies,such as the trace amount detection.
