Electro-optic modulator is a key component for on-chip optical signal processing.An electro-optic phase modulator based on multilayer graphene embedded in silicon nitride waveguide is demonstrated to fulfill low-power...Electro-optic modulator is a key component for on-chip optical signal processing.An electro-optic phase modulator based on multilayer graphene embedded in silicon nitride waveguide is demonstrated to fulfill low-power operation.Finite element method is adopted to investigate the interaction enhancement between the graphene flake and the optical mode.The impact of multilayer graphene on the performance of phase modulator is studied comprehensively.Simulation results show that the modulation efficiency improves with the increment of graphene layer number,as well as the modulation length.The 3-dB bandwidth of around 48 GHz is independent of graphene layer number and length.Compared to modulator with two-or four-layer graphene,the six-layer graphene/silicon nitride waveguide modulator can realizeπphase shift at a low-power consumption of 14 fJ/bit when the modulation length is 240μm.展开更多
The novel BaTiO3/BiFeO3/TiO2 multilayer heterojunction is prepared on a fluorine-doped tinoxide(FTO) substrate by the sol–gel method. The results indicate that the Pt/Ba TiO3/BiFeO3/TiO2/FTO heterojunction exhibits s...The novel BaTiO3/BiFeO3/TiO2 multilayer heterojunction is prepared on a fluorine-doped tinoxide(FTO) substrate by the sol–gel method. The results indicate that the Pt/Ba TiO3/BiFeO3/TiO2/FTO heterojunction exhibits stable bipolar resistive switching characteristic, good retention performance, and reversal characteristic. Under different pulse voltages and light fields, four stable resistance states can also be realized. The analysis shows that the main conduction mechanism of the resistive switching characteristic of the heterojunction is space charge limited current(SCLC) effect. After the comprehensive analysis of the band diagram and the P–E ferroelectric property of the multilayer heterojunction, we can deduce that the SCLC is formed by the effect of the oxygen vacancy which is controlled by ferroelectric polarizationmodulated change of interfacial barrier. And the effective photo-generated carrier also plays a regulatory role in resistance state(RS), which is formed by the double ferroelectric layer Ba TiO3/BiFeO3 under different light fields. This research is of potential application values for developing the multi-state non-volatile resistance random access memory(RRAM) devices based on ferroelectric materials.展开更多
A novel scheme for generating optical chaos is proposed and experimentally demonstrated,which supports to simultaneously produce two low-correlation chaotic signals with wideband spectrum and suppressed time-delay-sig...A novel scheme for generating optical chaos is proposed and experimentally demonstrated,which supports to simultaneously produce two low-correlation chaotic signals with wideband spectrum and suppressed time-delay-signature(TDS).In the proposed scheme,we use the output of an external-cavity semiconductor laser(ECSL)as the driving signal of a phase modulator to modulate the output of a CW laser.Then the phase-modulated continuous-wave(CW)light is split into two parts,one is injected back into the ECSL that outputs one chaotic signal,while the other part is passed through a dispersion module for generating another chaotic signal simultaneously.The experimental results prove that the proposed scheme has three merits.Firstly,it can improve the bandwidth of ECSL-based chaos by several times,and simultaneously generate another wideband flat-spectrum chaotic signal.Secondly,the undesired TDS characteristics of the simultaneously-generated chaotic signals can be efficiently suppressed to an indistinguishable level within a wide parameter range,as such the complexities of the chaotic signals are considerably high.Thirdly,the correlation coefficient between these two simultaneously-generated chaotic signals is smaller than 0.1.The proposed scheme provides an attractive solution for parallel multiple chaos generation,and shows great potential for multiple channel chaos communications and multiple random bit generations.展开更多
High-performance thin film lithium niobate(LN) electro-optic modulators with low cost are in demand. Based on photolithography and wet etching, we experimentally demonstrate a thin film LN Mach–Zehnder modulator with...High-performance thin film lithium niobate(LN) electro-optic modulators with low cost are in demand. Based on photolithography and wet etching, we experimentally demonstrate a thin film LN Mach–Zehnder modulator with a 3 d B bandwidth exceeding 110 GHz, which shows the potential of boosting the throughput and reducing cost. The fabricated modulator also exhibits a comparable low half-wave voltage-length product of ~2.37 V · cm, a high extinction ratio of >23 d B, and the propagation loss of optical waveguides of ~0.2 d B/cm. Besides, six-level pulse amplitude modulation up to 250 Gb/s is successfully achieved.展开更多
Electro-optic modulators,which convert electrical signals onto the transmission light,are key devices in electro-optic modulating systems.Modulation efficiency is one of the most important parameters of an electro-opt...Electro-optic modulators,which convert electrical signals onto the transmission light,are key devices in electro-optic modulating systems.Modulation efficiency is one of the most important parameters of an electro-optic modulator,which directly determines the footprint and power consumption of the device.Generally,modulation efficiency strongly depends on the electro-optic response of the crystal.The Pb(In_(1/2)Nb_(1/2))O_(3)-Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3)(PIN-PMN-PT)single crystal with giant electro-optic coefficient(λ_(c))and high transparency indicates the potential to achieve greatly enhanced modulation efficiency.In this study,a prototype PIN-PMN-PT phase modulator was fabricated based on a titanium(Ti)in-diffusion waveguide,which is reported for the first time.The influences of titanium in-diffusion on the composition and domain structure of the PIN-PMN-PT single crystal were studied by transmission electron microscopy(TEM)and piezoelectric force microscopy(PFM),respectively.Finally,a half-wave voltage(V_(π))of 2.3 V was obtained using a device with 6-mm-long(L)electrodes.Furthermore,the electro-optic modulation efficiency(V_(π)L)was calculated as 1.38 V-cm,which was approximately one order of magnitude lower than that of commercial lithium niobate(LiNbO_(3),LN)phase modulators.Such enhanced modulation efficiency indicates more compact device and lower power consumption,which is of great significance for electro-optic modulation systems used in micro-fiber gyroscope,integrated photonic devices,etc.展开更多
Using finite element method, lots of calculating focusing on polymer electro-optic modulators with ultra-broadband were done, a few structures were analyzed. Coplanar waveguide electrode system was advanced, a few rea...Using finite element method, lots of calculating focusing on polymer electro-optic modulators with ultra-broadband were done, a few structures were analyzed. Coplanar waveguide electrode system was advanced, a few real examples was given.展开更多
A novel high-speed electro-optic (EO) polymer modulator based on long period gratings (LPG) is designed. Using the theory of multi-cladding optical waveguide, we achieved relationship between modulate voltage and LPG&...A novel high-speed electro-optic (EO) polymer modulator based on long period gratings (LPG) is designed. Using the theory of multi-cladding optical waveguide, we achieved relationship between modulate voltage and LPG's resonant wavelength.展开更多
In a D-shaped twin-core fiber(DTCF),the central core is insensitive to the variation of the external environment,while the other core is highly sensitive.As an electro-optic polymer coated on a DTCF,the coupling betwe...In a D-shaped twin-core fiber(DTCF),the central core is insensitive to the variation of the external environment,while the other core is highly sensitive.As an electro-optic polymer coated on a DTCF,the coupling between the two cores varies with voltages applied to the polymer.Based on this,a superior all-fiber modulator is proposed that bears little coupling loss,prohibits mode mismatch,and provides a more stable working circumstance.A half-wave driving voltage(V_π)of 1.26 V is achieved.Moreover,a high modulation depth of 40 dB can be realized for a voltage of 2.7 V at a 1550 nm wavelength.展开更多
Energy-efficient electro-optic modulators are at the heart of short-reach optical interconnects,and silicon photonics is considered the leading technology for realizing such devices.However,the performance of all-sili...Energy-efficient electro-optic modulators are at the heart of short-reach optical interconnects,and silicon photonics is considered the leading technology for realizing such devices.However,the performance of all-silicon devices is limited by intrinsic material properties.In particular,the absence of linear electro-optic effects in silicon renders the integration of energy-efficient photonic–electronic interfaces challenging.Silicon–organic hybrid(SOH)integration can overcome these limitations by combining nanophotonic silicon waveguides with organic cladding materials,thereby offering the prospect of designing optical properties by molecular engineering.In this paper,we demonstrate an SOH Mach–Zehnder modulator with unprecedented efficiency:the 1-mm-long device consumes only 0.7 fJ bit^(-1) to generate a 12.5 Gbit s^(-1) data stream with a bit-error ratio below the threshold for hard-decision forward-error correction.This power consumption represents the lowest value demonstrated for a non-resonant Mach–Zehnder modulator in any material system.It is enabled by a novel class of organic electro-optic materials that are designed for high chromophore density and enhanced molecular orientation.The device features an electro-optic coefficient of r33<180 pm V^(-1) and can be operated at data rates of up to 40 Gbit s^(-1).展开更多
A novel thin-film lithium niobate(TFLN) electro-optic modulator is proposed and demonstrated. LiNbO_(3)-silica hybrid waveguide is adopted to maintain low optical loss for an electrode spacing as narrow as 3 μm, resu...A novel thin-film lithium niobate(TFLN) electro-optic modulator is proposed and demonstrated. LiNbO_(3)-silica hybrid waveguide is adopted to maintain low optical loss for an electrode spacing as narrow as 3 μm, resulting in a low halfwave-voltage length product of only 1.7 V·cm. Capacitively loaded traveling-wave electrodes are employed to reduce the microwave loss, while a quartz substrate is used in place of a silicon substrate to achieve velocity matching. The fabricated TFLN modulator with a 5-mm-long modulation region exhibits a half-wave voltage of 3.4 V and a merely less than 2 d B roll-off in an electro-optic response up to 67 GHz.展开更多
Multi-lane integrated transmitter chips are key components in future compact optical modules to realize high-speed optical interconnects.Thin-film lithium niobate(TFLN)photonics have emerged as a promising platform fo...Multi-lane integrated transmitter chips are key components in future compact optical modules to realize high-speed optical interconnects.Thin-film lithium niobate(TFLN)photonics have emerged as a promising platform for achieving high-performance chip-scale optical systems.Combining a coarse wavelength-division multiplexing(CWDM)devices using fabrication-tolerant angled multimode interferometer structure and high-performance electro-optical modulators,we demonstrate monolithic on-chip four-channel CWDM transmitter on the TFLN platform for the first time.The four-channel CWDM transmitter enables high-speed transmissions of 100 Gb/s data rate per wavelength channel(i.e.,an aggregated date rate of 400 Gb/s).展开更多
Many applications of metasurfaces require an ability to dynamically change their properties in the time domain. Electrical tuning techniques are of particular interest, since they pave a way to on-chip integration of ...Many applications of metasurfaces require an ability to dynamically change their properties in the time domain. Electrical tuning techniques are of particular interest, since they pave a way to on-chip integration of metasurfaces with optoelectronic devices.In this work, we propose and experimentally demonstrate an electro-optic lithium niobate(EO-LN) metasurface that shows dynamic modulations to phase retardation of transmitted light. Quasi-bound states in the continuum(QBIC) are observed from this metasurface. By applying external electric voltages, the refractive index of lithium niobate(LN) is changed by Pockels EO nonlinearity, leading to efficient phase modulations to the transmitted light around the QBIC wavelength. The EO-LN metasurface developed in this study opens up new routes for potential applications in the field of displaying, pulse shaping, and spatial light modulating.展开更多
Rationally designed organic electro-optic (OEO) materials demonstrate ultra-large electro-optic (EO) activities, affording inorganic-organic hybrid photonic devices with low drive voltage, large bandwidth, low energy ...Rationally designed organic electro-optic (OEO) materials demonstrate ultra-large electro-optic (EO) activities, affording inorganic-organic hybrid photonic devices with low drive voltage, large bandwidth, low energy consumption, and small footprint. OEO materials hold the potential to achieve EO coefficients (r_(33)) over 1000 pm/V. Over the past decade, however, the best performance of OEO materials is limited to 300—600 pm·V^(−1). This is partly because of the concern of increasing dipole moment and optical loss due to the redshifted absorbance of high hyperpolarizability chromophores. Recent advance of theory-guided design enables the OEO materials to achieve greatly enhanced hyperpolarizability and EO activity with dipole moment and propagation loss within acceptable constraints. Simultaneously, progress in hybrid device designs has greatly shortened the length of modulating waveguide, which resulted in significantly reduced sensitivity to propagation loss from redshifted absorption of OEO materials. Driven by theory-guided design method, several high-performance OEO materials have been presented with greatly enhanced EO coefficients beyond 1000 pm·V^(−1). This brief review summarizes the strategies to improve the EO activity including molecular engineering and hyperpolarizability, highlights the recent great progress in design of high-performance OEO materials, and discusses the problems needed to be solved in application for current OEO materials.展开更多
基金the National Key Research and Development Program of China(Grant No.2019YFB2203001)the National Natural Science Foundation of China(Grant Nos.61675087,61875069,and 61605057)the Science and Technology Development Plan of Jilin Province,China(Grant No.JJKH20190118KJ).
文摘Electro-optic modulator is a key component for on-chip optical signal processing.An electro-optic phase modulator based on multilayer graphene embedded in silicon nitride waveguide is demonstrated to fulfill low-power operation.Finite element method is adopted to investigate the interaction enhancement between the graphene flake and the optical mode.The impact of multilayer graphene on the performance of phase modulator is studied comprehensively.Simulation results show that the modulation efficiency improves with the increment of graphene layer number,as well as the modulation length.The 3-dB bandwidth of around 48 GHz is independent of graphene layer number and length.Compared to modulator with two-or four-layer graphene,the six-layer graphene/silicon nitride waveguide modulator can realizeπphase shift at a low-power consumption of 14 fJ/bit when the modulation length is 240μm.
基金Project supported by the Scientific Research Program of Hunan Provincial Education Department,China(Grant No.18C0232)the International Cooperative Extension Program of Changsha University of Science and Technology,China(Grant No.2019IC35)
文摘The novel BaTiO3/BiFeO3/TiO2 multilayer heterojunction is prepared on a fluorine-doped tinoxide(FTO) substrate by the sol–gel method. The results indicate that the Pt/Ba TiO3/BiFeO3/TiO2/FTO heterojunction exhibits stable bipolar resistive switching characteristic, good retention performance, and reversal characteristic. Under different pulse voltages and light fields, four stable resistance states can also be realized. The analysis shows that the main conduction mechanism of the resistive switching characteristic of the heterojunction is space charge limited current(SCLC) effect. After the comprehensive analysis of the band diagram and the P–E ferroelectric property of the multilayer heterojunction, we can deduce that the SCLC is formed by the effect of the oxygen vacancy which is controlled by ferroelectric polarizationmodulated change of interfacial barrier. And the effective photo-generated carrier also plays a regulatory role in resistance state(RS), which is formed by the double ferroelectric layer Ba TiO3/BiFeO3 under different light fields. This research is of potential application values for developing the multi-state non-volatile resistance random access memory(RRAM) devices based on ferroelectric materials.
基金This work was supported by the National Natural Science Foundation of China(Grant no.62171087,61671119)the Sichuan Science and Technology Program(Grant no.2021JDJQ0023)the Fundamental Research Funds for the Central Universities(Grant no.ZYGX2019J003).
文摘A novel scheme for generating optical chaos is proposed and experimentally demonstrated,which supports to simultaneously produce two low-correlation chaotic signals with wideband spectrum and suppressed time-delay-signature(TDS).In the proposed scheme,we use the output of an external-cavity semiconductor laser(ECSL)as the driving signal of a phase modulator to modulate the output of a CW laser.Then the phase-modulated continuous-wave(CW)light is split into two parts,one is injected back into the ECSL that outputs one chaotic signal,while the other part is passed through a dispersion module for generating another chaotic signal simultaneously.The experimental results prove that the proposed scheme has three merits.Firstly,it can improve the bandwidth of ECSL-based chaos by several times,and simultaneously generate another wideband flat-spectrum chaotic signal.Secondly,the undesired TDS characteristics of the simultaneously-generated chaotic signals can be efficiently suppressed to an indistinguishable level within a wide parameter range,as such the complexities of the chaotic signals are considerably high.Thirdly,the correlation coefficient between these two simultaneously-generated chaotic signals is smaller than 0.1.The proposed scheme provides an attractive solution for parallel multiple chaos generation,and shows great potential for multiple channel chaos communications and multiple random bit generations.
基金This work was supported by the National Natural Science Foundation of China(Nos.61690194 and 61911530162)。
文摘High-performance thin film lithium niobate(LN) electro-optic modulators with low cost are in demand. Based on photolithography and wet etching, we experimentally demonstrate a thin film LN Mach–Zehnder modulator with a 3 d B bandwidth exceeding 110 GHz, which shows the potential of boosting the throughput and reducing cost. The fabricated modulator also exhibits a comparable low half-wave voltage-length product of ~2.37 V · cm, a high extinction ratio of >23 d B, and the propagation loss of optical waveguides of ~0.2 d B/cm. Besides, six-level pulse amplitude modulation up to 250 Gb/s is successfully achieved.
基金supported by the National Natural Science Foundation of China(Grant Nos.52102143,51772239,62001369,62075088,and 51761145024)Shaanxi Province Project(Grant Nos.2017ktpt-21 and 2018TD-024)Jiangxi Technological Innovation Guidance Science and Technology Plan(Grant No.S20212BDH80017).
文摘Electro-optic modulators,which convert electrical signals onto the transmission light,are key devices in electro-optic modulating systems.Modulation efficiency is one of the most important parameters of an electro-optic modulator,which directly determines the footprint and power consumption of the device.Generally,modulation efficiency strongly depends on the electro-optic response of the crystal.The Pb(In_(1/2)Nb_(1/2))O_(3)-Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3)(PIN-PMN-PT)single crystal with giant electro-optic coefficient(λ_(c))and high transparency indicates the potential to achieve greatly enhanced modulation efficiency.In this study,a prototype PIN-PMN-PT phase modulator was fabricated based on a titanium(Ti)in-diffusion waveguide,which is reported for the first time.The influences of titanium in-diffusion on the composition and domain structure of the PIN-PMN-PT single crystal were studied by transmission electron microscopy(TEM)and piezoelectric force microscopy(PFM),respectively.Finally,a half-wave voltage(V_(π))of 2.3 V was obtained using a device with 6-mm-long(L)electrodes.Furthermore,the electro-optic modulation efficiency(V_(π)L)was calculated as 1.38 V-cm,which was approximately one order of magnitude lower than that of commercial lithium niobate(LiNbO_(3),LN)phase modulators.Such enhanced modulation efficiency indicates more compact device and lower power consumption,which is of great significance for electro-optic modulation systems used in micro-fiber gyroscope,integrated photonic devices,etc.
基金The project is supported by Basic Research Foundation of Tsinghua University, No: JZ2000005.
文摘Using finite element method, lots of calculating focusing on polymer electro-optic modulators with ultra-broadband were done, a few structures were analyzed. Coplanar waveguide electrode system was advanced, a few real examples was given.
文摘A novel high-speed electro-optic (EO) polymer modulator based on long period gratings (LPG) is designed. Using the theory of multi-cladding optical waveguide, we achieved relationship between modulate voltage and LPG's resonant wavelength.
基金financially supported by the National Natural Science Foundation of China under Grant No.61525501
文摘In a D-shaped twin-core fiber(DTCF),the central core is insensitive to the variation of the external environment,while the other core is highly sensitive.As an electro-optic polymer coated on a DTCF,the coupling between the two cores varies with voltages applied to the polymer.Based on this,a superior all-fiber modulator is proposed that bears little coupling loss,prohibits mode mismatch,and provides a more stable working circumstance.A half-wave driving voltage(V_π)of 1.26 V is achieved.Moreover,a high modulation depth of 40 dB can be realized for a voltage of 2.7 V at a 1550 nm wavelength.
基金This work was supported by the European Research Council(ERC Starting Grant‘EnTeraPIC’,number 280145)by the Alfried Krupp von Bohlen und Halbach Foundation,and by the Initiative and Networking Fund of the Helmholtz Association+7 种基金We further acknowledge support by the DFG Center for Functional Nanostructuresby the Karlsruhe International Research School on Teratronics,by the Karlsruhe School of Optics and Photonicsby the Karlsruhe Nano-Micro Facility,by the DFG Major Research Instrumentation Programmeby the EU-FP7 projects PHOXTROT and BigPIPESby Deutsche Forschungsgemeinschaftby the Open Access Publishing Fund of Karlsruhe Institute of TechnologyFurther financial support was obtained from the National Science Foundation(DMR-0905686,DMR-0120967)the Air Force Office of Scientific Research(FA9550-09-1-0682)
文摘Energy-efficient electro-optic modulators are at the heart of short-reach optical interconnects,and silicon photonics is considered the leading technology for realizing such devices.However,the performance of all-silicon devices is limited by intrinsic material properties.In particular,the absence of linear electro-optic effects in silicon renders the integration of energy-efficient photonic–electronic interfaces challenging.Silicon–organic hybrid(SOH)integration can overcome these limitations by combining nanophotonic silicon waveguides with organic cladding materials,thereby offering the prospect of designing optical properties by molecular engineering.In this paper,we demonstrate an SOH Mach–Zehnder modulator with unprecedented efficiency:the 1-mm-long device consumes only 0.7 fJ bit^(-1) to generate a 12.5 Gbit s^(-1) data stream with a bit-error ratio below the threshold for hard-decision forward-error correction.This power consumption represents the lowest value demonstrated for a non-resonant Mach–Zehnder modulator in any material system.It is enabled by a novel class of organic electro-optic materials that are designed for high chromophore density and enhanced molecular orientation.The device features an electro-optic coefficient of r33<180 pm V^(-1) and can be operated at data rates of up to 40 Gbit s^(-1).
基金supported in part by the National Key R&D Program of China(No.2018YFB2201701)National Natural Science Foundation of China(Nos.61975093,61927811,61991443,61822404,61974080,61904093,and 61875104)+1 种基金Key Lab Program of BNRist(No.BNR2019ZS01005),China Postdoctoral Science Foundation(No.2019T120090)Collaborative Innovation Centre of Solid-State Lighting and Energy-Saving Electronics。
文摘A novel thin-film lithium niobate(TFLN) electro-optic modulator is proposed and demonstrated. LiNbO_(3)-silica hybrid waveguide is adopted to maintain low optical loss for an electrode spacing as narrow as 3 μm, resulting in a low halfwave-voltage length product of only 1.7 V·cm. Capacitively loaded traveling-wave electrodes are employed to reduce the microwave loss, while a quartz substrate is used in place of a silicon substrate to achieve velocity matching. The fabricated TFLN modulator with a 5-mm-long modulation region exhibits a half-wave voltage of 3.4 V and a merely less than 2 d B roll-off in an electro-optic response up to 67 GHz.
基金This work is supported partially by the National Major Research and Development Program(2019YFB1803902)National Natural Science Foundation of China(NSFC)(62135012,62105107)+3 种基金Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2021R01001)Guangdong Basic and Applied Basic Research Foundation(2021A 1515012215,2021B1515120057)Science and Technology Planning Project of Guangdong Province(2019A050510039)Fundamental Research Funds for the Central Universities(2021QNA5001).
文摘Multi-lane integrated transmitter chips are key components in future compact optical modules to realize high-speed optical interconnects.Thin-film lithium niobate(TFLN)photonics have emerged as a promising platform for achieving high-performance chip-scale optical systems.Combining a coarse wavelength-division multiplexing(CWDM)devices using fabrication-tolerant angled multimode interferometer structure and high-performance electro-optical modulators,we demonstrate monolithic on-chip four-channel CWDM transmitter on the TFLN platform for the first time.The four-channel CWDM transmitter enables high-speed transmissions of 100 Gb/s data rate per wavelength channel(i.e.,an aggregated date rate of 400 Gb/s).
基金supported by the Guangdong Major Project of Basic and Applied Basic Research (Grant No.2020B0301030009)the National Key R&D Program of China (Grant Nos.2017YFA0305100,2017YFA0303800,and 2019YFA0705000)+5 种基金the National Natural Science Foundation of China (Grant Nos.92050114,91750204,61775106,11904182,12074200,and 11774185)the 111 Project (Grant No.B07013)PCSIRT (Grant No.IRT0149)the Open Research Program of Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang ProvinceFundamental Research Funds for the Central Universities (Grant Nos.010-63201003,01063201008,and 010-63201009)Tianjin Youth Talent Support Program。
文摘Many applications of metasurfaces require an ability to dynamically change their properties in the time domain. Electrical tuning techniques are of particular interest, since they pave a way to on-chip integration of metasurfaces with optoelectronic devices.In this work, we propose and experimentally demonstrate an electro-optic lithium niobate(EO-LN) metasurface that shows dynamic modulations to phase retardation of transmitted light. Quasi-bound states in the continuum(QBIC) are observed from this metasurface. By applying external electric voltages, the refractive index of lithium niobate(LN) is changed by Pockels EO nonlinearity, leading to efficient phase modulations to the transmitted light around the QBIC wavelength. The EO-LN metasurface developed in this study opens up new routes for potential applications in the field of displaying, pulse shaping, and spatial light modulating.
基金support of the National Natural Science Foundation of China(52172048,52103221)the Shandong Provincial Natural Science Foundation(ZR2021ZD06,ZR2021QB024,ZR2021QB179)the Fundamental Research Funds of Shandong University.
文摘Rationally designed organic electro-optic (OEO) materials demonstrate ultra-large electro-optic (EO) activities, affording inorganic-organic hybrid photonic devices with low drive voltage, large bandwidth, low energy consumption, and small footprint. OEO materials hold the potential to achieve EO coefficients (r_(33)) over 1000 pm/V. Over the past decade, however, the best performance of OEO materials is limited to 300—600 pm·V^(−1). This is partly because of the concern of increasing dipole moment and optical loss due to the redshifted absorbance of high hyperpolarizability chromophores. Recent advance of theory-guided design enables the OEO materials to achieve greatly enhanced hyperpolarizability and EO activity with dipole moment and propagation loss within acceptable constraints. Simultaneously, progress in hybrid device designs has greatly shortened the length of modulating waveguide, which resulted in significantly reduced sensitivity to propagation loss from redshifted absorption of OEO materials. Driven by theory-guided design method, several high-performance OEO materials have been presented with greatly enhanced EO coefficients beyond 1000 pm·V^(−1). This brief review summarizes the strategies to improve the EO activity including molecular engineering and hyperpolarizability, highlights the recent great progress in design of high-performance OEO materials, and discusses the problems needed to be solved in application for current OEO materials.
