Diverse natural organisms possess stimulus-responsive structures to adapt to the surrounding environment.Inspired by nature,researchers have developed various smart stimulus-responsive structures with adjustable prope...Diverse natural organisms possess stimulus-responsive structures to adapt to the surrounding environment.Inspired by nature,researchers have developed various smart stimulus-responsive structures with adjustable properties and functions to address the demands of ever-changing application environments that are becoming more intricate.Among many fabrication methods for stimulus-responsive structures,femtosecond laser direct writing(FsLDW)has received increasing attention because of its high precision,simplicity,true three-dimensional machining ability,and wide applicability to almost all materials.This paper systematically outlines state-of-the-art research on stimulus-responsive structures prepared by FsLDW.Based on the introduction of femtosecond laser-matter interaction and mainstream FsLDW-based manufacturing strategies,different stimulating factors that can trigger structural responses of prepared intelligent structures,such as magnetic field,light,temperature,pH,and humidity,are emphatically summarized.Various applications of functional structures with stimuli-responsive dynamic behaviors fabricated by FsLDW,as well as the present obstacles and forthcoming development opportunities,are discussed.展开更多
manufacturing of biomimetic micro/nanostructures due to its specific advantages including high precision,simplicity,and compatibility for diverse materials in comparison with other methods(e.g.ion etching,sol-gel proc...manufacturing of biomimetic micro/nanostructures due to its specific advantages including high precision,simplicity,and compatibility for diverse materials in comparison with other methods(e.g.ion etching,sol-gel process,chemical vapor deposition,template method,and self-assembly).These biomimetic micro/nanostructured surfaces are of significant interest for academic and industrial research due to their wide range of potential applications,including self-cleaning surfaces,oil-water separation,and fog collection.This review presents the inherent relationship between natural organisms,fabrication methods,micro/nanostructures and their potential applications.Thereafter,we throw a list of current fabrication strategies so as to highlight the advantages of FLDW in manufacturing bioinspired microstructured surfaces.Subsequently,we summarize a variety of typical bioinspired designs(e.g.lotus leaf,pitcher plant,rice leaf,butterfly wings,etc)for diverse multifunctional micro/nanostructures through extreme femtosecond laser processing technology.Based on the principle of interfacial chemistry and geometrical optics,we discuss the potential applications of these functional micro/nanostructures and assess the underlying challenges and opportunities in the extreme fabrication of bioinspired micro/nanostructures by FLDW.This review concludes with a follow up and an outlook of femtosecond laser processing in biomimetic domains.展开更多
This paper reports the fabrication of regular large-area laser-induced periodic surface structures(LIPSSs)in indium tin oxide(ITO)films via femtosecond laser direct writing focused by a cylindrical lens.The regular LI...This paper reports the fabrication of regular large-area laser-induced periodic surface structures(LIPSSs)in indium tin oxide(ITO)films via femtosecond laser direct writing focused by a cylindrical lens.The regular LIPSSs exhibited good properties as nanowires,with a resistivity almost equal to that of the initial ITO film.By changing the laser fluence,the nanowire resistances could be tuned from 15 to 73 kΩ/mm with a consistency of±10%.Furthermore,the average transmittance of the ITO films with regular LIPSSs in the range of 1200-2000 nm was improved from 21%to 60%.The regular LIPSS is promising for transparent electrodes of nano-optoelectronic devices-particularly in the near-infrared band.展开更多
The femtosecond laser direct writing technique is a highly precise processing method that enables the rapid fabrication of three-dimensional(3D)micro-and nanoscale photonic structures in transparent materials.By focus...The femtosecond laser direct writing technique is a highly precise processing method that enables the rapid fabrication of three-dimensional(3D)micro-and nanoscale photonic structures in transparent materials.By focusing ultrashort laser pulses into transparent optical materials,such as crystals and glasses,it is possible to efficiently modify specific optical properties,including refractive indices and ferroelectric domains,at the laser focus.By carefully designing and optimizing the movement trajectory of the femtosecond laser,one can achieve periodic modulation of the optical features of these materials in 3D space.The resulting changes in material properties are closely linked to both the processing parameters of the femtosecond laser and the types of materials used.Through ongoing optimization of these parameters,desired periodic photonic structures can be created in specific transparent optical materials,leading to the development of 3D nonlinear photonic crystals(NPCs)and 3D waveguide arrays.Femtosecond laser direct writing breaks through the limitations of traditional techniques to fabricate 3D NPCs[e.g.,3D lithium niobate(LiNbO_(3))NPCs]and complex waveguide arrays(e.g.,3D helical waveguide arrays),realizing a paradigm shift in the fabrication of complex periodic photonic structures.To date,femtosecond-laser-written 3D NPCs and waveguide arrays have found extensive applications in integrated photonics,nonlinear optics,quantum optics,and topological photonics.We highlight recent advancements in femtosecond-laser-written 3D NPCs and waveguide arrays,such as pivotal breakthroughs in the fabrication of nanoscale-resolution 3D NPCs in LiNbO_(3).Finally,several potential research directions,such as the formation mechanism of domain wall and inducing millimeter-scale domain inversion with femtosecond Bessel beam,have been proposed at the end of this article.展开更多
In this work,we report a novel soft diffractive micro-optics,called‘microscale kinoform phase-type lens(micro-KPL)’,which is fabricated by femtosecond laser direct writing(FsLDW)using bovine serum albumin(BSA)as bui...In this work,we report a novel soft diffractive micro-optics,called‘microscale kinoform phase-type lens(micro-KPL)’,which is fabricated by femtosecond laser direct writing(FsLDW)using bovine serum albumin(BSA)as building blocks and flexible polydimethylsiloxane(PDMS)slices as substrates.By carefully optimizing various process parameters of FsLDW(e.g.,average laser power density,scanning step,exposure time on a single point and protein concentration),the as-formed protein micro-KPLs exhibit excellent surface quality,well-defined three-dimensional(3D)geometry and distinctive optical properties,even in relatively harsh operation environments(for instance,in strong acid or base).Laser shaping,imaging and other optical performances can be easily achieved.More importantly,micro-KPLs also have unique flexible and stretchable properties as well as good biocompatibility and biodegradability.Therefore,such protein hydrogel-based micro-optics may have great potential applications,such as in flexible and stretchable photonics and optics,soft integrated optical microsystems and bioimplantable devices.展开更多
The development of modern information technology has led to significant demand for microoptical elements with complex surface profiles and nanoscale surface roughness.Therefore,various micro-and nanoprocessing techniq...The development of modern information technology has led to significant demand for microoptical elements with complex surface profiles and nanoscale surface roughness.Therefore,various micro-and nanoprocessing techniques are used to fabricate microoptical elements and systems.Femtosecond laser direct writing(FsLDW)uses ultrafast pulses and the ultraintense instantaneous energy of a femtosecond laser for micro-nano fabrication.FsLDW exhibits various excellent properties,including nonlinear multiphoton absorption,high-precision processing beyond the diffraction limit,and the universality of processable materials,demonstrating its unique advantages and potential applications in three-dimensional(3D)micro-nano manufacturing.FsLDW has demonstrated its value in the fabrication of various microoptical systems.This study details three typical principles of FsLDW,several design considerations to improve processing performance,processable materials,imaging/nonimaging microoptical elements,and their stereoscopic systems.Finally,a summary and perspective on the future research directions for FsLDW-enabled microoptical elements and stereoscopic systems are provided.展开更多
In this Letter,waveguide beam splitters(1×3)with type I modifications are fabricated in a LiNbO_(3) crystal by femtosecond laser direct writing.The influence of the relative positions of three sub-waveguides on p...In this Letter,waveguide beam splitters(1×3)with type I modifications are fabricated in a LiNbO_(3) crystal by femtosecond laser direct writing.The influence of the relative positions of three sub-waveguides on power splitting ratios are investigated in detail and the corresponding output intensities as functions of the relative positions in the numerical simulation are plotted,which are in good accordance with the experimental results.In addition,the waveguide beam splitter with a 1:1:1 splitting ratio is fabricated by changing the relative widths of the three branch-waveguides.Guiding performances at 532 nm are measured and analyzed by a typical end-face coupling system.The simulation and experimental results demonstrate that the beam splitting ratio of the waveguide splitter can be precisely regulated by the positions and widths of the sub-waveguides.展开更多
Femtosecond laser direct writing provides an efficient approach to fabricating single nitrogen vacancy(NV) color centers with a relatively high yield. Different from previously reported NV color centers with a random ...Femtosecond laser direct writing provides an efficient approach to fabricating single nitrogen vacancy(NV) color centers with a relatively high yield. Different from previously reported NV color centers with a random distribution in a bulk diamond or nanocrystals, this gives an opportunity to study the photophysical properties of single NV color centers with precise numbers and positions. However, ultrafast studies on single NV color centers prepared by localization femtosecond laser direct writing are still rare, especially for the graphitization inside a diamond and its relationship with single NV color centers. Here, we report the broadband transient absorption(TA) spectroscopic features of the graphitization and NV color centers in a diamond fabricated by localization femtosecond laser direct writing at room temperature under 400 nm excitation. In comparison with the graphene oxide film, the bleaching features of the graphitization point array in a diamond are similar to reduced graphene oxide,accompanied by excited state absorption signals from local carbon atom vacancy defects in graphene-like structures induced by laser writing. On the other hand, transient features of laser processing array containing single NV color centers with a yield of~50% are different from those of the graphitization point array. Our findings suggest that for ultrashort pulse processing of diamonds, broadband TA spectral signals are sensitive to the surrounding atomic environment of processing sites, which could be applied to laser writing point defects in other materials used as solid-state single photon sources.展开更多
Recently,transmitting diverse signals in different cores of a multicore fiber(MCF)has greatly improved the communication capacity of a single fiber.In such an MCF-based communication system,mux/demux devices with broa...Recently,transmitting diverse signals in different cores of a multicore fiber(MCF)has greatly improved the communication capacity of a single fiber.In such an MCF-based communication system,mux/demux devices with broad bandwidth are of great significance.In this work,we design and fabricate a 19-channel mux/demux device based on femtosecond laser direct writing.The fabricated mux/demux device possesses an average insertion loss of 0.88 dB and intercore crosstalk of no more than−29.1 dB.Moreover,the fabricated mux/demux device features a broad bandwidth across the C+L band.Such a mux/demux device enables low-loss 19-core fiber(de)multiplexing over the whole C+L band,showing a convincing potential value in wavelength-space division multiplexing applications.In addition,a 19-core fiber fan-in/fan-out system is also established based on a pair of mux/demux devices in this work.展开更多
High-density interconnect(HDI)soft electronics that can integrate multiple individual functions into one miniaturized monolithic system is promising for applications related to smart healthcare,soft robotics,and human...High-density interconnect(HDI)soft electronics that can integrate multiple individual functions into one miniaturized monolithic system is promising for applications related to smart healthcare,soft robotics,and human-machine interactions.However,despite the recent advances,the development of three-dimensional(3D)soft electronics with both high resolution and high integration is still challenging because of the lack of efficient manufacturing methods to guarantee interlayer alignment of the high-density vias and reliable interlayer electrical conductivity.Here,an advanced 3D laser printing pathway,based on femtosecond laser direct writing(FLDW),is demonstrated for preparing liquid metal(LM)-based any layer HDI soft electronics.FLDW technology,with the characteristics of high spatial resolution and high precision,allows the maskless fabrication of high-resolution embedded LM microchannels and high-density vertical interconnect accesses for 3D integrated circuits.High-aspect-ratio blind/through LM microstructures are formed inside the elastomer due to the supermetalphobicity induced during laser ablation.The LM-based HDI circuit featuring high resolution(~1.5μm)and high integration(10-layer electrical interconnection)is achieved for customized soft electronics,including various customized multilayer passive electric components,soft multilayer circuit,and cross-scale multimode sensors.The 3D laser printing method provides a versatile approach for developing chip-level soft electronics.展开更多
Bessel beams have multiple applications owing to their propagation-invariant properties,including particle trapping,optical coherence tomography,and material processing.However,traditional Bessel-beam shaping techniqu...Bessel beams have multiple applications owing to their propagation-invariant properties,including particle trapping,optical coherence tomography,and material processing.However,traditional Bessel-beam shaping techniques require bulky components,which limits the development of miniaturized optical systems for integration with other devices.Here,we report a novel femtosecond laser direct writing strategy for fabricating mesoscale(from submicrometer to subcentimeter)binary optical elements with microscale resolution.This strategy utilizes femtosecond beams with a long focal depth to increase throughput while reducing the constraints on critical sample positioning.As a demonstration,we manufactured and characterized a 2.2 mm diameter binary axicon.The experimentally measured quasi-Bessel beam intensity distribution and the numerical results were remarkably consistent,demonstrating a suitable tradeoff between the overall size,efficiency,and structural fidelity.Furthermore,a compact Bessel lens containing binary axicons was constructed and successfully used for femtosecond laser mask-less ablation of periodic grating-type surface plasmon polariton excitation units.The demonstrated approach shows significant potential for fabricating customizable integrated optical components.展开更多
ZnO nanomaterials have become appealing for next-generation micro/nanodevices owing to their remarkable functionality and outstanding performance.However,in-situ,one-step,patterned synthesis of ZnO nanomaterials with ...ZnO nanomaterials have become appealing for next-generation micro/nanodevices owing to their remarkable functionality and outstanding performance.However,in-situ,one-step,patterned synthesis of ZnO nanomaterials with small grain sizes and high specific surface areas remains challenging.While breakthroughs in laser-based synthesis techniques have enabled simultaneous growth and patterning of these materials,device integration restrictions owing to pre-prepared laser-absorbing layers remain a severe issue.Herein,we report a single-step femtosecond laser direct writing(FsLDW)method for fabricating ZnO nanomaterial micropatterns with a minimum linewidth of less than 1μm without requiring laser-absorbing layers.Furthermore,utilizing the grain-size modulation effect of glycerol,we successfully reduced the grain size and addressed the challenges of discontinuity and non-uniform product formation during FsLDW.Using this technique,we successfully fabricated a series of 2 micro-photodetectors with exceptional performance,a switching ratio of 105,and a responsivity of 10 A/W.Notably,the devices exhibited an ultralow dark current of less than 10 pA,more than one order of magnitude lower than the dark current of ZnO photodetectors under the same bias voltage—crucial for enhancing the signal-to-noise ratio and reducing the power consumption of photodetectors.The proposed method could be extended to preparing other metal-oxide nanomaterials and devices,thus providing new opportunities for developing customized,miniaturized,and integrated functional devices.展开更多
Integrated photonics is attracting considerable attention and has found many applications in both classical and quantum optics,fulfilling the requirements for the ever-growing complexity in modern optical experiments ...Integrated photonics is attracting considerable attention and has found many applications in both classical and quantum optics,fulfilling the requirements for the ever-growing complexity in modern optical experiments and big data communication.Femtosecond(fs)laser direct writing(FLDW)is an acknowledged technique for producing waveguides(WGs)in transparent glass that have been used to construct complex integrated photonic devices.FLDW possesses unique features,such as three-dimensional fabrication geometry,rapid prototyping,and single step fabrication,which are important for integrated communication devices and quantum photonic and astrophotonic technologies.To fully take advantage of FLDW,considerable efforts have been made to produce WGs over a large depth with low propagation loss,coupling loss,bend loss,and highly symmetrical mode field.We summarize the improved techniques as well as the mechanisms for writing high-performance WGs with controllable morphology of cross-section,highly symmetrical mode field,low loss,and high processing uniformity and efficiency,and discuss the recent progress of WGs in photonic integrated devices for communication,topological physics,quantum information processing,and astrophotonics.Prospective challenges and future research directions in this field are also pointed out.展开更多
.Nanochannel structures with a feature size deeply under the diffraction limit and a high aspect ratio hold huge biomedical significance,which is especially challenging to be realized on hard and brittle materials,suc....Nanochannel structures with a feature size deeply under the diffraction limit and a high aspect ratio hold huge biomedical significance,which is especially challenging to be realized on hard and brittle materials,such as silica,diamond,and sapphire.By simultaneously depositing the pulse energy on the surface and inside the sample,nanochannels with the smallest feature size of 18 nm(∼1∕30λ)and more than 200 aspect ratios are achieved inside silica,the mechanism of which can be concluded as the surface assisting material ejection effect.Both the experimental and theoretical results prove that the coaction of the superficial“hot domain”and internal hot domain dominates the generation of the nanochannels,which gives new insights into the laser-material interacting mechanisms and potentially promotes the corresponding application fields.展开更多
We report on high-performance waveguide lasers based on depressed-cladding waveguides fabricated by a femtosecond laser in Tm:YGG crystals.Pumped with a 1700-nm Raman fiber laser,the performances of Tm:YGG waveguide l...We report on high-performance waveguide lasers based on depressed-cladding waveguides fabricated by a femtosecond laser in Tm:YGG crystals.Pumped with a 1700-nm Raman fiber laser,the performances of Tm:YGG waveguide lasers have been investigated.Benefiting from the high quantum efficiency of an in-band pumping scheme and the high quality of depressed-cladding waveguides,the highest output power of 2.2 W has been achieved at 2μm,with a slope efficiency of 34.9%.This is,to the best of our knowledge,the highest power ever reported from such 2-μm waveguide lasers.Our work is of great significance to fabricate high-performance and high-power waveguide lasers in integrated photonics.展开更多
The emergence of dynamic optical switching has opened up new perspectives for lightening the ever growing load on the electrical switches and routers,to meet the increasing demand on high-speed and flexible data proce...The emergence of dynamic optical switching has opened up new perspectives for lightening the ever growing load on the electrical switches and routers,to meet the increasing demand on high-speed and flexible data processing and management in fiber-optic communications.Despite diversity schemes of optical switching in the single-mode regime,multi-mode switching of the hybrid fiber and chip system enabled by photonic integrated circuits,especially for the fiber-chip-fiber system,is still an outstanding challenge.Here,we propose and demonstrate the mode and polarization transmission and switching fiber-chip-fiber system with few-mode fibers(FMFs),including the FMF links for mode-and polarization-division multiplexing data transmission,the femtosecond(fs)-laser inscribed 3-dimensional(3D)photonic lantern silica chip for(de)multiplexing and coupling between FMFs and chip,and the topology-optimized N×N non-blocking 2-dimensional(2D)silicon switch array chip for switching and routing.Using 30-Gbaud quadrature phase-shift keying signals on wavelength-division multiplexing(WDM)channels,the WDM-compatible hybrid mode/polarization transmission,switching and routing system with FMFs,fs-laser inscribed silica(de)multiplexing chip and silicon switch array chip are demonstrated in the experiment with favorable operation performance.The demonstration may open the door for developing robust multi-dimensional optical data processing in fiber-optic communication systems with versatile fibers and chips.展开更多
Modern three-dimensional nanofabrication requires both additive and subtractive processes.However,both processes are largely isolated and generally regarded as incompatible with each other.In this study,we developed s...Modern three-dimensional nanofabrication requires both additive and subtractive processes.However,both processes are largely isolated and generally regarded as incompatible with each other.In this study,we developed simultaneous additive and subtractive fabrication processes using two-photon polymerization followed by femtosecond(fs)laser multiphoton ablation.To demonstrate the new capability,submicrometer polymer fibers containing periodic holes of 500-nm diameter and microfluidic channels of 1-mm diameter were successfully fabricated.This method combining both two-photon polymerization and fs laser ablation improves the nanofabrication efficiency and enables the fabrication of complex three-dimensional micro-/nanostructures,promising for a wide range of applications in integrated optics,microfluidics and microelectromechanical systems.展开更多
Nondeterministic-polynomial-time(NP)-complete problems are widely involved in various reallife scenarios but are still intractable in being solved efficiently on conventional computers.It is of great practical signifi...Nondeterministic-polynomial-time(NP)-complete problems are widely involved in various reallife scenarios but are still intractable in being solved efficiently on conventional computers.It is of great practical significance to construct versatile computing architectures that solve NP-complete problems with computational advantage.Here,we present a reconfigurable integrated photonic processor to efficiently solve a benchmark NP-complete problem,the subset sum problem.We show that in the case of successive primes,the photonic processor has genuinely surpassed electronic processors launched recently by taking advantage of the high propagation speed and vast parallelism of photons and state-of-the-art integrated photonic technology.Moreover,we are able to program the photonic processor to tackle different problem instances,relying on the tunable integrated modules,variable split junctions,which can be used to build a fully reconfigurable architecture potentially allowing 2^(N) configurations at most.Our experiments confirm the potential of the photonic processor as a versatile and efficient computing platform,suggesting a possible practical route to solving computationally hard problems at a large scale.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 52122511, 52105492, and 62005262)the National Key Research and Development Program of China (No. 2021YFF0502700)+2 种基金the Students’ Innovation and Entrepreneurship Foundation of USTC (Nos. CY2022G32 and XY2022G02CY)the USTC Research Funds of the Double First-Class Initiative (No. YD2340002009)CAS Project for Young Scientists in Basic Research (No. YSBR-049)
文摘Diverse natural organisms possess stimulus-responsive structures to adapt to the surrounding environment.Inspired by nature,researchers have developed various smart stimulus-responsive structures with adjustable properties and functions to address the demands of ever-changing application environments that are becoming more intricate.Among many fabrication methods for stimulus-responsive structures,femtosecond laser direct writing(FsLDW)has received increasing attention because of its high precision,simplicity,true three-dimensional machining ability,and wide applicability to almost all materials.This paper systematically outlines state-of-the-art research on stimulus-responsive structures prepared by FsLDW.Based on the introduction of femtosecond laser-matter interaction and mainstream FsLDW-based manufacturing strategies,different stimulating factors that can trigger structural responses of prepared intelligent structures,such as magnetic field,light,temperature,pH,and humidity,are emphatically summarized.Various applications of functional structures with stimuli-responsive dynamic behaviors fabricated by FsLDW,as well as the present obstacles and forthcoming development opportunities,are discussed.
基金The present work was supported by the National Natural Science Foundation of China(51805508)the Key Project of Equipment Pre-Research Field Fund of China(61409230310)and the Fundamental Research Funds for the Central Universities(WK2090090025).
文摘manufacturing of biomimetic micro/nanostructures due to its specific advantages including high precision,simplicity,and compatibility for diverse materials in comparison with other methods(e.g.ion etching,sol-gel process,chemical vapor deposition,template method,and self-assembly).These biomimetic micro/nanostructured surfaces are of significant interest for academic and industrial research due to their wide range of potential applications,including self-cleaning surfaces,oil-water separation,and fog collection.This review presents the inherent relationship between natural organisms,fabrication methods,micro/nanostructures and their potential applications.Thereafter,we throw a list of current fabrication strategies so as to highlight the advantages of FLDW in manufacturing bioinspired microstructured surfaces.Subsequently,we summarize a variety of typical bioinspired designs(e.g.lotus leaf,pitcher plant,rice leaf,butterfly wings,etc)for diverse multifunctional micro/nanostructures through extreme femtosecond laser processing technology.Based on the principle of interfacial chemistry and geometrical optics,we discuss the potential applications of these functional micro/nanostructures and assess the underlying challenges and opportunities in the extreme fabrication of bioinspired micro/nanostructures by FLDW.This review concludes with a follow up and an outlook of femtosecond laser processing in biomimetic domains.
基金We are grateful for financial supports from the Ministry of Science and Technology of China(Grant No.2021YFA1401100)National Natural Science Foundation of China(Grant Nos.12074123,11804227,91950112),and the Foundation of‘Manufacturing beyond limits’of Shanghai.
文摘This paper reports the fabrication of regular large-area laser-induced periodic surface structures(LIPSSs)in indium tin oxide(ITO)films via femtosecond laser direct writing focused by a cylindrical lens.The regular LIPSSs exhibited good properties as nanowires,with a resistivity almost equal to that of the initial ITO film.By changing the laser fluence,the nanowire resistances could be tuned from 15 to 73 kΩ/mm with a consistency of±10%.Furthermore,the average transmittance of the ITO films with regular LIPSSs in the range of 1200-2000 nm was improved from 21%to 60%.The regular LIPSS is promising for transparent electrodes of nano-optoelectronic devices-particularly in the near-infrared band.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204274,12174222,12304364,and 12361141815)Key Research and Development Program of Shandong Province(Grant No.2024ZLGX02-3)+1 种基金Natural Science Foundation of Shandong Province(Grant Nos.ZR2022QA033,ZR2021ZD02,and ZR2023QA125)Taishan Scholar Foundation of Shandong Province(Grant No.tspd20210303).
文摘The femtosecond laser direct writing technique is a highly precise processing method that enables the rapid fabrication of three-dimensional(3D)micro-and nanoscale photonic structures in transparent materials.By focusing ultrashort laser pulses into transparent optical materials,such as crystals and glasses,it is possible to efficiently modify specific optical properties,including refractive indices and ferroelectric domains,at the laser focus.By carefully designing and optimizing the movement trajectory of the femtosecond laser,one can achieve periodic modulation of the optical features of these materials in 3D space.The resulting changes in material properties are closely linked to both the processing parameters of the femtosecond laser and the types of materials used.Through ongoing optimization of these parameters,desired periodic photonic structures can be created in specific transparent optical materials,leading to the development of 3D nonlinear photonic crystals(NPCs)and 3D waveguide arrays.Femtosecond laser direct writing breaks through the limitations of traditional techniques to fabricate 3D NPCs[e.g.,3D lithium niobate(LiNbO_(3))NPCs]and complex waveguide arrays(e.g.,3D helical waveguide arrays),realizing a paradigm shift in the fabrication of complex periodic photonic structures.To date,femtosecond-laser-written 3D NPCs and waveguide arrays have found extensive applications in integrated photonics,nonlinear optics,quantum optics,and topological photonics.We highlight recent advancements in femtosecond-laser-written 3D NPCs and waveguide arrays,such as pivotal breakthroughs in the fabrication of nanoscale-resolution 3D NPCs in LiNbO_(3).Finally,several potential research directions,such as the formation mechanism of domain wall and inducing millimeter-scale domain inversion with femtosecond Bessel beam,have been proposed at the end of this article.
基金HBS thanks the National Science Foundation of China(Grant No.90923037)the National Basic Research Program of China(973 Program)(Grant No.2011CB013005)for support+1 种基金WFD thanks the National Science Foundation of China(Grant Nos.91123029,61077066,61137001 and 61127010)the 863 Project of China(Grant No.2012AA063302)for financial support.
文摘In this work,we report a novel soft diffractive micro-optics,called‘microscale kinoform phase-type lens(micro-KPL)’,which is fabricated by femtosecond laser direct writing(FsLDW)using bovine serum albumin(BSA)as building blocks and flexible polydimethylsiloxane(PDMS)slices as substrates.By carefully optimizing various process parameters of FsLDW(e.g.,average laser power density,scanning step,exposure time on a single point and protein concentration),the as-formed protein micro-KPLs exhibit excellent surface quality,well-defined three-dimensional(3D)geometry and distinctive optical properties,even in relatively harsh operation environments(for instance,in strong acid or base).Laser shaping,imaging and other optical performances can be easily achieved.More importantly,micro-KPLs also have unique flexible and stretchable properties as well as good biocompatibility and biodegradability.Therefore,such protein hydrogel-based micro-optics may have great potential applications,such as in flexible and stretchable photonics and optics,soft integrated optical microsystems and bioimplantable devices.
基金supported by the National Natural Science Foundation of China(Nos.62275044,62205174,61875036)the Jinan“20 New Colleges and Universities”Innovation Team Introduction Project(202228047).
文摘The development of modern information technology has led to significant demand for microoptical elements with complex surface profiles and nanoscale surface roughness.Therefore,various micro-and nanoprocessing techniques are used to fabricate microoptical elements and systems.Femtosecond laser direct writing(FsLDW)uses ultrafast pulses and the ultraintense instantaneous energy of a femtosecond laser for micro-nano fabrication.FsLDW exhibits various excellent properties,including nonlinear multiphoton absorption,high-precision processing beyond the diffraction limit,and the universality of processable materials,demonstrating its unique advantages and potential applications in three-dimensional(3D)micro-nano manufacturing.FsLDW has demonstrated its value in the fabrication of various microoptical systems.This study details three typical principles of FsLDW,several design considerations to improve processing performance,processable materials,imaging/nonimaging microoptical elements,and their stereoscopic systems.Finally,a summary and perspective on the future research directions for FsLDW-enabled microoptical elements and stereoscopic systems are provided.
基金supported by the National Natural Science Foundation of China(No.12274236)the Open Foundation of State Key Laboratory of Fluid Power and Mechatronic Systems(No.GZKF-202320).
文摘In this Letter,waveguide beam splitters(1×3)with type I modifications are fabricated in a LiNbO_(3) crystal by femtosecond laser direct writing.The influence of the relative positions of three sub-waveguides on power splitting ratios are investigated in detail and the corresponding output intensities as functions of the relative positions in the numerical simulation are plotted,which are in good accordance with the experimental results.In addition,the waveguide beam splitter with a 1:1:1 splitting ratio is fabricated by changing the relative widths of the three branch-waveguides.Guiding performances at 532 nm are measured and analyzed by a typical end-face coupling system.The simulation and experimental results demonstrate that the beam splitting ratio of the waveguide splitter can be precisely regulated by the positions and widths of the sub-waveguides.
基金supported by the National Natural Science Foundation of China (Grant Nos. 62175088, 61927814, 21773087, 21603083, 21903035)China Postdoctoral Science Foundation (Grant No. 2016M590259)。
文摘Femtosecond laser direct writing provides an efficient approach to fabricating single nitrogen vacancy(NV) color centers with a relatively high yield. Different from previously reported NV color centers with a random distribution in a bulk diamond or nanocrystals, this gives an opportunity to study the photophysical properties of single NV color centers with precise numbers and positions. However, ultrafast studies on single NV color centers prepared by localization femtosecond laser direct writing are still rare, especially for the graphitization inside a diamond and its relationship with single NV color centers. Here, we report the broadband transient absorption(TA) spectroscopic features of the graphitization and NV color centers in a diamond fabricated by localization femtosecond laser direct writing at room temperature under 400 nm excitation. In comparison with the graphene oxide film, the bleaching features of the graphitization point array in a diamond are similar to reduced graphene oxide,accompanied by excited state absorption signals from local carbon atom vacancy defects in graphene-like structures induced by laser writing. On the other hand, transient features of laser processing array containing single NV color centers with a yield of~50% are different from those of the graphitization point array. Our findings suggest that for ultrashort pulse processing of diamonds, broadband TA spectral signals are sensitive to the surrounding atomic environment of processing sites, which could be applied to laser writing point defects in other materials used as solid-state single photon sources.
基金supported by the National Natural Science Foundation of China(Grant Nos.62125503 and 62261160388)the Key R&D Program of Hubei Province of China(Grant Nos.2020BAB001 and 2021BAA024)+3 种基金the Key R&D Program of Guangdong Province(Grant No.2018B030325002)the Science and Technology Innovation Commission of Shenzhen(Grant No.JCYJ20200109114018750)the Open Projects Foundation(No.SKLD2201)of State Key Laboratory of Optical Fiber and Cable Manufacture Technology(YOFC)the Innovation Project of Optics Valley Laboratory(Grant No.OVL2021BG004).
文摘Recently,transmitting diverse signals in different cores of a multicore fiber(MCF)has greatly improved the communication capacity of a single fiber.In such an MCF-based communication system,mux/demux devices with broad bandwidth are of great significance.In this work,we design and fabricate a 19-channel mux/demux device based on femtosecond laser direct writing.The fabricated mux/demux device possesses an average insertion loss of 0.88 dB and intercore crosstalk of no more than−29.1 dB.Moreover,the fabricated mux/demux device features a broad bandwidth across the C+L band.Such a mux/demux device enables low-loss 19-core fiber(de)multiplexing over the whole C+L band,showing a convincing potential value in wavelength-space division multiplexing applications.In addition,a 19-core fiber fan-in/fan-out system is also established based on a pair of mux/demux devices in this work.
基金supported by the National Science Foundation of China under the Grant Nos.12127806 and 62175195the International Joint Research Laboratory for Micro/Nano Manufacturing and Measurement Technologies。
文摘High-density interconnect(HDI)soft electronics that can integrate multiple individual functions into one miniaturized monolithic system is promising for applications related to smart healthcare,soft robotics,and human-machine interactions.However,despite the recent advances,the development of three-dimensional(3D)soft electronics with both high resolution and high integration is still challenging because of the lack of efficient manufacturing methods to guarantee interlayer alignment of the high-density vias and reliable interlayer electrical conductivity.Here,an advanced 3D laser printing pathway,based on femtosecond laser direct writing(FLDW),is demonstrated for preparing liquid metal(LM)-based any layer HDI soft electronics.FLDW technology,with the characteristics of high spatial resolution and high precision,allows the maskless fabrication of high-resolution embedded LM microchannels and high-density vertical interconnect accesses for 3D integrated circuits.High-aspect-ratio blind/through LM microstructures are formed inside the elastomer due to the supermetalphobicity induced during laser ablation.The LM-based HDI circuit featuring high resolution(~1.5μm)and high integration(10-layer electrical interconnection)is achieved for customized soft electronics,including various customized multilayer passive electric components,soft multilayer circuit,and cross-scale multimode sensors.The 3D laser printing method provides a versatile approach for developing chip-level soft electronics.
基金supported by the National Natural Science Foundation of China(62227821)Shanghai Institute of Optics and Fine Mechanics,and Chinese Academy of Sciences(Open Fund of the State Key Laboratory of High Field Laser Physics).
文摘Bessel beams have multiple applications owing to their propagation-invariant properties,including particle trapping,optical coherence tomography,and material processing.However,traditional Bessel-beam shaping techniques require bulky components,which limits the development of miniaturized optical systems for integration with other devices.Here,we report a novel femtosecond laser direct writing strategy for fabricating mesoscale(from submicrometer to subcentimeter)binary optical elements with microscale resolution.This strategy utilizes femtosecond beams with a long focal depth to increase throughput while reducing the constraints on critical sample positioning.As a demonstration,we manufactured and characterized a 2.2 mm diameter binary axicon.The experimentally measured quasi-Bessel beam intensity distribution and the numerical results were remarkably consistent,demonstrating a suitable tradeoff between the overall size,efficiency,and structural fidelity.Furthermore,a compact Bessel lens containing binary axicons was constructed and successfully used for femtosecond laser mask-less ablation of periodic grating-type surface plasmon polariton excitation units.The demonstrated approach shows significant potential for fabricating customizable integrated optical components.
基金financially supported by the National Natural Science Foundation of China(Grant numbers 52275429 and 62205117)。
文摘ZnO nanomaterials have become appealing for next-generation micro/nanodevices owing to their remarkable functionality and outstanding performance.However,in-situ,one-step,patterned synthesis of ZnO nanomaterials with small grain sizes and high specific surface areas remains challenging.While breakthroughs in laser-based synthesis techniques have enabled simultaneous growth and patterning of these materials,device integration restrictions owing to pre-prepared laser-absorbing layers remain a severe issue.Herein,we report a single-step femtosecond laser direct writing(FsLDW)method for fabricating ZnO nanomaterial micropatterns with a minimum linewidth of less than 1μm without requiring laser-absorbing layers.Furthermore,utilizing the grain-size modulation effect of glycerol,we successfully reduced the grain size and addressed the challenges of discontinuity and non-uniform product formation during FsLDW.Using this technique,we successfully fabricated a series of 2 micro-photodetectors with exceptional performance,a switching ratio of 105,and a responsivity of 10 A/W.Notably,the devices exhibited an ultralow dark current of less than 10 pA,more than one order of magnitude lower than the dark current of ZnO photodetectors under the same bias voltage—crucial for enhancing the signal-to-noise ratio and reducing the power consumption of photodetectors.The proposed method could be extended to preparing other metal-oxide nanomaterials and devices,thus providing new opportunities for developing customized,miniaturized,and integrated functional devices.
基金This work was financially supported by the National Key R&D Program of China(2020YFB1805900)the National Natural Science Foundation of China(U20A20211,51902286,61775192,61905215,and 51772270)Open Funds of the State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,and the Fundamental Research Funds for the Central Universities.The authors declare no competing financial interest.
文摘Integrated photonics is attracting considerable attention and has found many applications in both classical and quantum optics,fulfilling the requirements for the ever-growing complexity in modern optical experiments and big data communication.Femtosecond(fs)laser direct writing(FLDW)is an acknowledged technique for producing waveguides(WGs)in transparent glass that have been used to construct complex integrated photonic devices.FLDW possesses unique features,such as three-dimensional fabrication geometry,rapid prototyping,and single step fabrication,which are important for integrated communication devices and quantum photonic and astrophotonic technologies.To fully take advantage of FLDW,considerable efforts have been made to produce WGs over a large depth with low propagation loss,coupling loss,bend loss,and highly symmetrical mode field.We summarize the improved techniques as well as the mechanisms for writing high-performance WGs with controllable morphology of cross-section,highly symmetrical mode field,low loss,and high processing uniformity and efficiency,and discuss the recent progress of WGs in photonic integrated devices for communication,topological physics,quantum information processing,and astrophotonics.Prospective challenges and future research directions in this field are also pointed out.
基金supported by the National Natural Science Foundation of China under Grant Nos.12127806,62175195,and 61875158the International Joint Research Laboratory for Micro/Nano Manufacturing and Measurement Technologies,and the Fundamental Research Funds for the Central Universities.
文摘.Nanochannel structures with a feature size deeply under the diffraction limit and a high aspect ratio hold huge biomedical significance,which is especially challenging to be realized on hard and brittle materials,such as silica,diamond,and sapphire.By simultaneously depositing the pulse energy on the surface and inside the sample,nanochannels with the smallest feature size of 18 nm(∼1∕30λ)and more than 200 aspect ratios are achieved inside silica,the mechanism of which can be concluded as the surface assisting material ejection effect.Both the experimental and theoretical results prove that the coaction of the superficial“hot domain”and internal hot domain dominates the generation of the nanochannels,which gives new insights into the laser-material interacting mechanisms and potentially promotes the corresponding application fields.
基金supported by the Natural Science Foundation of Shandong Province(No.ZR2022QA033)the National Natural Science Foundation of China(No.12204274)+1 种基金the Key Research and Development Program of Shandong Province(No.2024ZLGX02-3)the project PID2022141499OB-100,funded by MICIU/AEI/10.13039/501100011033/and by FEDER/UE。
文摘We report on high-performance waveguide lasers based on depressed-cladding waveguides fabricated by a femtosecond laser in Tm:YGG crystals.Pumped with a 1700-nm Raman fiber laser,the performances of Tm:YGG waveguide lasers have been investigated.Benefiting from the high quantum efficiency of an in-band pumping scheme and the high quality of depressed-cladding waveguides,the highest output power of 2.2 W has been achieved at 2μm,with a slope efficiency of 34.9%.This is,to the best of our knowledge,the highest power ever reported from such 2-μm waveguide lasers.Our work is of great significance to fabricate high-performance and high-power waveguide lasers in integrated photonics.
基金National Key R&D Program of China(2019YFB2203604)National Natural Science Foundation of China(NSFC)(62125503,62261160388)+3 种基金Key R&D Program of Hubei Province of China(2020BAB001,2021BAA024)Key R&D Program of Guangdong Province(2018B030325002)Shenzhen Science and Technology Program(JCYJ20200109114018750)Innovation Project of Optics Valley Laboratory(OVL2021BG004).
文摘The emergence of dynamic optical switching has opened up new perspectives for lightening the ever growing load on the electrical switches and routers,to meet the increasing demand on high-speed and flexible data processing and management in fiber-optic communications.Despite diversity schemes of optical switching in the single-mode regime,multi-mode switching of the hybrid fiber and chip system enabled by photonic integrated circuits,especially for the fiber-chip-fiber system,is still an outstanding challenge.Here,we propose and demonstrate the mode and polarization transmission and switching fiber-chip-fiber system with few-mode fibers(FMFs),including the FMF links for mode-and polarization-division multiplexing data transmission,the femtosecond(fs)-laser inscribed 3-dimensional(3D)photonic lantern silica chip for(de)multiplexing and coupling between FMFs and chip,and the topology-optimized N×N non-blocking 2-dimensional(2D)silicon switch array chip for switching and routing.Using 30-Gbaud quadrature phase-shift keying signals on wavelength-division multiplexing(WDM)channels,the WDM-compatible hybrid mode/polarization transmission,switching and routing system with FMFs,fs-laser inscribed silica(de)multiplexing chip and silicon switch array chip are demonstrated in the experiment with favorable operation performance.The demonstration may open the door for developing robust multi-dimensional optical data processing in fiber-optic communication systems with versatile fibers and chips.
基金This research work was financially supported by National Science Foundation(CMMI 0900419 and 0758199)National Natural Science Foundation of China(grant no.90923039)。
文摘Modern three-dimensional nanofabrication requires both additive and subtractive processes.However,both processes are largely isolated and generally regarded as incompatible with each other.In this study,we developed simultaneous additive and subtractive fabrication processes using two-photon polymerization followed by femtosecond(fs)laser multiphoton ablation.To demonstrate the new capability,submicrometer polymer fibers containing periodic holes of 500-nm diameter and microfluidic channels of 1-mm diameter were successfully fabricated.This method combining both two-photon polymerization and fs laser ablation improves the nanofabrication efficiency and enables the fabrication of complex three-dimensional micro-/nanostructures,promising for a wide range of applications in integrated optics,microfluidics and microelectromechanical systems.
基金supported by the National Key R&D Program of China (Grants Nos. 2019YFA0308703, 2019YFA07063022017YFA0303700)+7 种基金the National Natural Science Foundation of China (NSFC)(Grant Nos. 62235012, 12104299,61734005, 11761141014, 11690033, 11904299, and 12304342)the Innovation Program for Quantum Science and Technology(Grant Nos. 2021ZD0301500 and 2021ZD0300700)the Science and Technology Commission of Shanghai Municipality(STCSM)(Grant Nos. 20JC1416300, 2019SHZDZX01,21ZR1432800, and 22QA1404600)the Shanghai Municipal Education Commission (SMEC)(Grant No. 2017-01-07-00-02-E00049)the China Postdoctoral Science Foundation (Grant Nos. 2022T150415, 2021M692094, and 2020M671091)the Startup Fund for Young Faculty at SJTU (SFYF at SJTU)additional support from a Shanghai Talent Programsupport from the Zhiyuan Innovative Research Center of Shanghai Jiao Tong University
文摘Nondeterministic-polynomial-time(NP)-complete problems are widely involved in various reallife scenarios but are still intractable in being solved efficiently on conventional computers.It is of great practical significance to construct versatile computing architectures that solve NP-complete problems with computational advantage.Here,we present a reconfigurable integrated photonic processor to efficiently solve a benchmark NP-complete problem,the subset sum problem.We show that in the case of successive primes,the photonic processor has genuinely surpassed electronic processors launched recently by taking advantage of the high propagation speed and vast parallelism of photons and state-of-the-art integrated photonic technology.Moreover,we are able to program the photonic processor to tackle different problem instances,relying on the tunable integrated modules,variable split junctions,which can be used to build a fully reconfigurable architecture potentially allowing 2^(N) configurations at most.Our experiments confirm the potential of the photonic processor as a versatile and efficient computing platform,suggesting a possible practical route to solving computationally hard problems at a large scale.
