Since the first observation of parity-time（PT） symmetry in optics, varied interesting phenomena have been discovered in both theories and experiments, such as PT phase transition and unidirectional invisibility, whi...Since the first observation of parity-time（PT） symmetry in optics, varied interesting phenomena have been discovered in both theories and experiments, such as PT phase transition and unidirectional invisibility, which turns PT-symmetric optics into a hotspot in research. Here, we report on the one-way localized Fabry-Pérot（FP） resonance, where a welldesigned PT optical resonator may operate at exceptional points with bidirectional transparency but unidirectional field localization. Overtones of such one-way localized FP resonance can be classified into a blue shifted branch and a red shifted branch. Therefore, the fundamental resonant frequency is not the lowest one. We find that the spatial field distributions of the overtones at the same absolute order are almost the same, even though their frequencies are quite different.展开更多
Optical bistability(OB)is capable of rapidly and reversibly transforming a parameter of an optical signal from one state to another,and homologous nonlinear optical bistable devices are core components of high-speed a...Optical bistability(OB)is capable of rapidly and reversibly transforming a parameter of an optical signal from one state to another,and homologous nonlinear optical bistable devices are core components of high-speed all-optical communication and all-optical networks.In this paper,we theoretically investigated the controllable OB from a Fabry-Pérot(FP)cavity with a nonlinear three-dimensional Dirac semimetal(3D DSM)in the terahertz band.The OB stems from the third-order nonlinear bulk conductivity of the 3D DSM and the resonance mode has a positive effect on the generation of OB.This FP cavity structure is able to tune the OB because the transmittance and the reflectance can be modulated by the Fermi energy of the 3D DSM.We believe that this FP cavity configuration could provide a reference concept for realizing tunable bistable devices.展开更多
In this paper, we observe experimentally the optical bistability induced by the side-mode injection power and wave- length detuning in a single mode Fabry-P6rot laser diode （SMFP-LD）. Results show that the bistabili...In this paper, we observe experimentally the optical bistability induced by the side-mode injection power and wave- length detuning in a single mode Fabry-P6rot laser diode （SMFP-LD）. Results show that the bistability characteristics of the dominant and injected modes are strongly dependent on the injected input optical power and wavelength detuning in an SMFP-LD. We observe three types of hysteresis loops： counterclockwise, clockwise, and butterfly hysteresis with various loop widths. In the case of a bistability loop caused by injection power, the transition from counterclockwise to clockwise in the hysteresis direction with the wavelength detuning from 0.028 nm to 0.112 nm is observed in a way of butterfly hys- teresis for the dominant mode by increasing the wavelength detuning. The width of hysteresis loop, induced by wavelength detuning is also changed while the injection power is enhanced from -7 dBm to -5 dBm.展开更多
This paper proposes a low-profile, aperture-shared dual-band bidirectional circularly polarized (CP) antenna. The design incorporates a partially reflective surface (PRS) and a multifunctional transmission-reflection ...This paper proposes a low-profile, aperture-shared dual-band bidirectional circularly polarized (CP) antenna. The design incorporates a partially reflective surface (PRS) and a multifunctional transmission-reflection integrated metasurface, enabling the integration of CP Fabry-Pérot cavity antenna (FPCA) and CP folded reflectarray (FRA), while preserving circular polarization purity and delivering high gain performance. In this design, the PRS acts as the reflector for the FRA at 8 GHz, while the multifunctional metasurface serves as the reflector for the FPCA at 8 GHz and provides phase compensation for the FRA at 13 GHz. Consequently, the FPCA and FRA can share the same aperture with high aperture reuse efficiency. The antenna achieves high gain across both frequency bands, with peak gains of 19.4 dBic and 22.8 dBic, respectively, without complex feeding networks. Leveraging the advantage of low focal-length-to-diameter ratio of the FRA, the array’s profile is reduced, with a height-to-diameter ratio of only 0.46.展开更多
By using a graded-index multimode fiber （GI-MMF） with a relatively flat index profile and high refractive index of the fiber core, a microextrinsic fiber-optic Fabry Prot interferometric （MEFPI） strain sensor is f...By using a graded-index multimode fiber （GI-MMF） with a relatively flat index profile and high refractive index of the fiber core, a microextrinsic fiber-optic Fabry Prot interferometric （MEFPI） strain sensor is fabricated through chemical etching and fusion splicing. Higher reflectance of the microcavity is obtained due to the less-curved inner wall in the center of the fiber core after etching and higher index contrast between the GI-MMF core and air. The maximum reflection of the sensor is enhanced 12 dB than that obtained by etching of the Er- or B-doped fibers. High fringe contrast of 22 dB is obtained. The strain and temperature responses of the MEFPI sensors are investigated in this experiment. Good linearity and high sensitivity are achieved, with wavelength-strain and wavelength-temperature sensitivities of 7.82 pm/με and 5.01 pm/°C, respectively.展开更多
Good linearity and wide dynamic range are the advantages of asymmetric Fabry-Pérot （F-P） interferometric cavity, whose realization has been long for. Based on optical thin film characteristic matrix theory, an ...Good linearity and wide dynamic range are the advantages of asymmetric Fabry-Pérot （F-P） interferometric cavity, whose realization has been long for. Based on optical thin film characteristic matrix theory, an asymmetric F-P interferometric cavity with good linearity and wide dynamic range is designed. And by choosing the material of two different thin metallic layers, the asymmetric F-P interferometric cavity is successfully fabricated. The design theory and method of this asymmetric F-P interferometric cavity have been described in detailed. In this paper an asymmetric F-P interferometric cavity used in fiber optical sensor is reported.展开更多
Fabry-Pérot(FP)microcavities have attracted tremendous attention in recent years due to their favorable optical characteristics of the high quality(Q)factor and small mode volume.In this work,we presented a novel...Fabry-Pérot(FP)microcavities have attracted tremendous attention in recent years due to their favorable optical characteristics of the high quality(Q)factor and small mode volume.In this work,we presented a novel approach that utilized the soft lithography and imprinting technology to incorporate the convex micro-lens array structure into the FP(FP-lens)cavity.A strong mode-profile restriction of the micro-lens simultaneously reduced the mode volume and enhanced the Q factor,exhibiting high tolerance to non-parallelism of mirrors compared with that of the plane-plane FP(PP-FP)microcavities.In the experiment,the Q factor of the FP-lens cavity was measured to be 8.145×10^(4),which exhibited a 5.6-fold increase than that of the PP-FP cavity.Furthermore,we experimentally measured the refractive index sensing performance of the FP-lens cavity with the sensitivity of 594.7 nm/RIU and a detection limit of 4.26×10^(–7)RIU.On the basis of this superior sensing performance,the FP-lens cavity has the great potential for applications in biosensors.展开更多
A novel gain measurement technique based on the integration of the measured amplified spontaneous emission spectrum multiplying a phase function over one longitudinal mode interval is proposed for Fabry-Perot semicond...A novel gain measurement technique based on the integration of the measured amplified spontaneous emission spectrum multiplying a phase function over one longitudinal mode interval is proposed for Fabry-Perot semiconductor lasers.展开更多
A novel long wavelength photodetector with dual-wavelength spectral response is designed and fabricated using a step-shaped Fabry-Perot （F-P） filter structure. The step-shaped GaAs/A1GaAs distributed Bragg reflector...A novel long wavelength photodetector with dual-wavelength spectral response is designed and fabricated using a step-shaped Fabry-Perot （F-P） filter structure. The step-shaped GaAs/A1GaAs distributed Bragg reflectors and the InP PIN photodetector are grown on a GaAs substrate using low pressure metal organic chemical vapor deposition. High quality GaAs/InP heteroepitaxy is realized by employing a thin low temperature buffer layer. The photodetector structure is optimized by theoretical simulation. This device has a dual-peak distance of 19 nm （1558 and 1 577 nm）. The 3-dB bandwidth of 16 GHz is simultaneously obtained with peak ouantum efficiencies of 8.5% and 8.6% around 1 .55R and 1 .577 nm respectively展开更多
The influence of GaAs substrate on the transmission performance of a multi-film Fabry-P＇erot filter （FPF）,fabricated by metalorganic chemical vapor deposition epitaxial growth on GaAs substrate,is investigated usin...The influence of GaAs substrate on the transmission performance of a multi-film Fabry-P＇erot filter （FPF）,fabricated by metalorganic chemical vapor deposition epitaxial growth on GaAs substrate,is investigated using the transfer matrix method.On the basis of the theoretical simulation,we determine that the quality of the resonant transmission peak of this epitaxially grown FPF （EG-FPF） deteriorates through splitting when the substrate is taken into account.Rapid periodic oscillation of peak-transmittivity along with the alteration of substrate thickness is also observed in the simulation results.Finally,a remarkably improved transmission performance of the EG-FPF is obtained by thinning the substrate down to a suitable thickness range through well-controlled grinding and polishing.展开更多
The scale mismatch between nanoscale biomolecules and sub-wavelength light hinders circular dichroism(CD)spectroscopy for chiral small molecule sensing.In this study,we propose a high quality-factor(Q-factor)optical c...The scale mismatch between nanoscale biomolecules and sub-wavelength light hinders circular dichroism(CD)spectroscopy for chiral small molecule sensing.In this study,we propose a high quality-factor(Q-factor)optical cavity that offers a breakthrough solution to the intrinsic trade-off between optical chirality density and mode loss.A spin-preserving chiral metasurface utilizes bound states in the continuum(BIC)-guided mode resonance(GMR)degenerate modes to achieve a high Q-factor,while ensuring the preservation of chirality purity for circularly polarized light propagating within the cavity via spin-locking mechanism.Experimental results demonstrate that the BIC-GMR degenerate state enables near-perfect transmission CD up to 0.99,without requiring symmetry breaking.Full-wave simulations further predict that this synergistically enhanced system can achieve a Q-factor as high as 10037 and generate a localized field in the molecular interaction region with an optical chirality density enhancement of up to 400-fold,leading to 5025-fold amplification of the CD signal.This study establishes a foundation for detecting low-concentration chiral molecules,reveals high-Q enhancement,and advances chiral toward single-molecule sensitivity,opening new research avenues in chiral biosensing.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674119,11404125,and 11574389)the financial support from the Bird Nest Plan of HUST,Chinasupported by One Hundred-Talent Plan of Chinese Academy of Sciences
文摘Since the first observation of parity-time（PT） symmetry in optics, varied interesting phenomena have been discovered in both theories and experiments, such as PT phase transition and unidirectional invisibility, which turns PT-symmetric optics into a hotspot in research. Here, we report on the one-way localized Fabry-Pérot（FP） resonance, where a welldesigned PT optical resonator may operate at exceptional points with bidirectional transparency but unidirectional field localization. Overtones of such one-way localized FP resonance can be classified into a blue shifted branch and a red shifted branch. Therefore, the fundamental resonant frequency is not the lowest one. We find that the spatial field distributions of the overtones at the same absolute order are almost the same, even though their frequencies are quite different.
基金Project supported by the Wenzhou Major Science and Technology Innovation Project:Research and Industrialization of Key Technologies for Intelligent Dynamic Ultrahigh Pressure Microfluidizer(Grant No.ZG2023012)Wenzhou Major Science and Technology Innovation PR Project(Grant No.ZG2022011)+3 种基金the National Natural Science Foundation of China(Grant No.62305254)the Scientific Research Fund of the Natural Science Foundation of Hunan Province(Grant No.2022JJ30394)the Changsha Natural Science Foundation(Grant Nos.kq2202236 and kq2202246)the Science and Technology Project of Jiangxi Provincial Education Department(Grant No.GJJ190911).
文摘Optical bistability(OB)is capable of rapidly and reversibly transforming a parameter of an optical signal from one state to another,and homologous nonlinear optical bistable devices are core components of high-speed all-optical communication and all-optical networks.In this paper,we theoretically investigated the controllable OB from a Fabry-Pérot(FP)cavity with a nonlinear three-dimensional Dirac semimetal(3D DSM)in the terahertz band.The OB stems from the third-order nonlinear bulk conductivity of the 3D DSM and the resonance mode has a positive effect on the generation of OB.This FP cavity structure is able to tune the OB because the transmittance and the reflectance can be modulated by the Fermi energy of the 3D DSM.We believe that this FP cavity configuration could provide a reference concept for realizing tunable bistable devices.
基金supported by the National Natural Science Foundation of China(Grant No.61205111)the Open Foundation of State Key Laboratory of Millimeter Waves,China(Grant No.K201219)the Natural Science Foundation of Chongqing Normal University,China(Grant No.2011XLZ06)
文摘In this paper, we observe experimentally the optical bistability induced by the side-mode injection power and wave- length detuning in a single mode Fabry-P6rot laser diode （SMFP-LD）. Results show that the bistability characteristics of the dominant and injected modes are strongly dependent on the injected input optical power and wavelength detuning in an SMFP-LD. We observe three types of hysteresis loops： counterclockwise, clockwise, and butterfly hysteresis with various loop widths. In the case of a bistability loop caused by injection power, the transition from counterclockwise to clockwise in the hysteresis direction with the wavelength detuning from 0.028 nm to 0.112 nm is observed in a way of butterfly hys- teresis for the dominant mode by increasing the wavelength detuning. The width of hysteresis loop, induced by wavelength detuning is also changed while the injection power is enhanced from -7 dBm to -5 dBm.
文摘This paper proposes a low-profile, aperture-shared dual-band bidirectional circularly polarized (CP) antenna. The design incorporates a partially reflective surface (PRS) and a multifunctional transmission-reflection integrated metasurface, enabling the integration of CP Fabry-Pérot cavity antenna (FPCA) and CP folded reflectarray (FRA), while preserving circular polarization purity and delivering high gain performance. In this design, the PRS acts as the reflector for the FRA at 8 GHz, while the multifunctional metasurface serves as the reflector for the FPCA at 8 GHz and provides phase compensation for the FRA at 13 GHz. Consequently, the FPCA and FRA can share the same aperture with high aperture reuse efficiency. The antenna achieves high gain across both frequency bands, with peak gains of 19.4 dBic and 22.8 dBic, respectively, without complex feeding networks. Leveraging the advantage of low focal-length-to-diameter ratio of the FRA, the array’s profile is reduced, with a height-to-diameter ratio of only 0.46.
基金supported by the State Key Laboratory of Advanced Optical Communication Systems and Networks,China
文摘By using a graded-index multimode fiber （GI-MMF） with a relatively flat index profile and high refractive index of the fiber core, a microextrinsic fiber-optic Fabry Prot interferometric （MEFPI） strain sensor is fabricated through chemical etching and fusion splicing. Higher reflectance of the microcavity is obtained due to the less-curved inner wall in the center of the fiber core after etching and higher index contrast between the GI-MMF core and air. The maximum reflection of the sensor is enhanced 12 dB than that obtained by etching of the Er- or B-doped fibers. High fringe contrast of 22 dB is obtained. The strain and temperature responses of the MEFPI sensors are investigated in this experiment. Good linearity and high sensitivity are achieved, with wavelength-strain and wavelength-temperature sensitivities of 7.82 pm/με and 5.01 pm/°C, respectively.
基金This work was supported by the National "863" Project of China (No. 2003AA311022)the National "973" Project of China (No. 2004CB719804)the National Natural Science Foundation of China (No. 10274108)the Natural Science Foundation of Guangdong Province of China.
文摘Good linearity and wide dynamic range are the advantages of asymmetric Fabry-Pérot （F-P） interferometric cavity, whose realization has been long for. Based on optical thin film characteristic matrix theory, an asymmetric F-P interferometric cavity with good linearity and wide dynamic range is designed. And by choosing the material of two different thin metallic layers, the asymmetric F-P interferometric cavity is successfully fabricated. The design theory and method of this asymmetric F-P interferometric cavity have been described in detailed. In this paper an asymmetric F-P interferometric cavity used in fiber optical sensor is reported.
基金supported by the National Natural Science Foundation of China(Grant No.62175035)the Natural Science Foundation of Shanghai(Grant No.21ZR1407400)Open Foundation of Key Laboratory of Laser Device Technology,China North Industries Group Corporation Limited(Grant No.KLLDT202108).
文摘Fabry-Pérot(FP)microcavities have attracted tremendous attention in recent years due to their favorable optical characteristics of the high quality(Q)factor and small mode volume.In this work,we presented a novel approach that utilized the soft lithography and imprinting technology to incorporate the convex micro-lens array structure into the FP(FP-lens)cavity.A strong mode-profile restriction of the micro-lens simultaneously reduced the mode volume and enhanced the Q factor,exhibiting high tolerance to non-parallelism of mirrors compared with that of the plane-plane FP(PP-FP)microcavities.In the experiment,the Q factor of the FP-lens cavity was measured to be 8.145×10^(4),which exhibited a 5.6-fold increase than that of the PP-FP cavity.Furthermore,we experimentally measured the refractive index sensing performance of the FP-lens cavity with the sensitivity of 594.7 nm/RIU and a detection limit of 4.26×10^(–7)RIU.On the basis of this superior sensing performance,the FP-lens cavity has the great potential for applications in biosensors.
基金This work was supported by the National Nature Science Foundation of China under grants No. 60225011major state basic research program under grant No. G2000036606.
文摘A novel gain measurement technique based on the integration of the measured amplified spontaneous emission spectrum multiplying a phase function over one longitudinal mode interval is proposed for Fabry-Perot semiconductor lasers.
基金supported by the National"973"Pro-gram of China(No.2010CB327600)the National Natural Science Foundation of China(No.61020106007)+3 种基金the Fundamental Research Funds for the Central University(No.BUPT2011RC0403)the National"863"Program of China(No.2007AA03Z418)the 111 Project of China(No.B07005)the Program for Changjiang Scholars and Innovative Research Team in University MOE,China(No.IRT0609)
文摘A novel long wavelength photodetector with dual-wavelength spectral response is designed and fabricated using a step-shaped Fabry-Perot （F-P） filter structure. The step-shaped GaAs/A1GaAs distributed Bragg reflectors and the InP PIN photodetector are grown on a GaAs substrate using low pressure metal organic chemical vapor deposition. High quality GaAs/InP heteroepitaxy is realized by employing a thin low temperature buffer layer. The photodetector structure is optimized by theoretical simulation. This device has a dual-peak distance of 19 nm （1558 and 1 577 nm）. The 3-dB bandwidth of 16 GHz is simultaneously obtained with peak ouantum efficiencies of 8.5% and 8.6% around 1 .55R and 1 .577 nm respectively
基金supported by the National "973" Program of China (No. 2010CB327600)the National "863" Program of China (No. 2007AA03Z418)+3 种基金the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT0609)the Fundamental Research Funds for the Central University (No. BUPT2011RC0403)the National Natural Science Foundation of China (No. 61020106007)the "111" Project of China (No. B07005)
文摘The influence of GaAs substrate on the transmission performance of a multi-film Fabry-P＇erot filter （FPF）,fabricated by metalorganic chemical vapor deposition epitaxial growth on GaAs substrate,is investigated using the transfer matrix method.On the basis of the theoretical simulation,we determine that the quality of the resonant transmission peak of this epitaxially grown FPF （EG-FPF） deteriorates through splitting when the substrate is taken into account.Rapid periodic oscillation of peak-transmittivity along with the alteration of substrate thickness is also observed in the simulation results.Finally,a remarkably improved transmission performance of the EG-FPF is obtained by thinning the substrate down to a suitable thickness range through well-controlled grinding and polishing.
基金financially supported by the POSCO-POSTECH-RIST Convergence Research Center program funded by POSCOthe National Research Foundation (NRF) grant (RS-2024-00462912) funded by the Ministry of Science and ICT (MSIT) of the Korean government+4 种基金partially supported by National Natural Science Foundation of China (Nos. 12274074, 12134013)Natural Science Foundation of Jiangsu Province (BK20242024)China Scholarship Council (202406090137)Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX24_0379)the NRF Ph.D. fellowship (RS-202525437554) funded by the Ministry of Education (MOE) of the Korean government
文摘The scale mismatch between nanoscale biomolecules and sub-wavelength light hinders circular dichroism(CD)spectroscopy for chiral small molecule sensing.In this study,we propose a high quality-factor(Q-factor)optical cavity that offers a breakthrough solution to the intrinsic trade-off between optical chirality density and mode loss.A spin-preserving chiral metasurface utilizes bound states in the continuum(BIC)-guided mode resonance(GMR)degenerate modes to achieve a high Q-factor,while ensuring the preservation of chirality purity for circularly polarized light propagating within the cavity via spin-locking mechanism.Experimental results demonstrate that the BIC-GMR degenerate state enables near-perfect transmission CD up to 0.99,without requiring symmetry breaking.Full-wave simulations further predict that this synergistically enhanced system can achieve a Q-factor as high as 10037 and generate a localized field in the molecular interaction region with an optical chirality density enhancement of up to 400-fold,leading to 5025-fold amplification of the CD signal.This study establishes a foundation for detecting low-concentration chiral molecules,reveals high-Q enhancement,and advances chiral toward single-molecule sensitivity,opening new research avenues in chiral biosensing.
