Random fiber lasers(RFLs)have attracted extensive attention due to their rich physical properties and wide applications.Here,a RFL using a cascaded fiber loop mirror(CFLM)is proposed and presented.A CFLM with 10 fiber...Random fiber lasers(RFLs)have attracted extensive attention due to their rich physical properties and wide applications.Here,a RFL using a cascaded fiber loop mirror(CFLM)is proposed and presented.A CFLM with 10 fiber loop mirrors(FLMs)is simulated by the transfer matrix method and used to provide random feedback.Multiple spikes are observed in both the simulated and measured reflection spectra.The RFL operates in a single longitudinal mode near the threshold and a time-varying multilongitudinal mode at higher pump powers.The RFL exhibits a time-varying radio-frequency spectrum.The Lévy–Gaussian distribution transition is observed,as in many RFLs.The operation mechanism of the lasing longitudinal modes and the impact of complex mode competition and mode hopping on the output characteristics are discussed through experimental and theoretical results.In this study,we unveil an artificial random feedback structure and pave another way for the realization of RFLs,which should be a platform for multidisciplinary studies in complex systems.展开更多
Artificially designed hyperbolic metamaterials(HMMs)with extraordinary optical anisotropy can support highly sensitive plasmonic sensing detections,showcasing significant potential for advancements in medical research...Artificially designed hyperbolic metamaterials(HMMs)with extraordinary optical anisotropy can support highly sensitive plasmonic sensing detections,showcasing significant potential for advancements in medical research and clinical diagnostics.In this study,we develop a gold nanoridge HMM and disclose the plasmonic sensing physical mechanism based on this type ofHMMthrough theoretical and experimental studies.We determine that the high modal group velocity of plasmonic guided modes stemming from a large transverse permittivity of HMMs directly results in high sensitivity.By combining electron-beam lithography,oxygen plasma etching,and electroplating,the fabricated gold nanoridge array possesses an extremely high structural filling ratio that is difficult to obtain through conventional processes.This leads to a large transverse permittivity and enables highly confined and ultra-sensitive bulk plasmon-polariton(BPP)guided modes.By exciting these modes in the visible to near-infrared region,we achieve a record sensitivity of 53,300 nm/RIU and a figure of merit of 533.Furthermore,the developed plasmonic nanoridge HMM sensor exhibits an enhanced sensitivity of two orders of magnitude compared to that of the same type of HMM sensor in label-free biomolecule detection.Our study not only offers a promising avenue for label-free biosensing but also holds great potential to enhance early disease detection and monitoring.展开更多
We demonstrate a silicon-based microwave photonic filter(MPF) with flattop passband and adjustable bandwidth. The proposed MPF is realized by using a 10 th-order microring resonator(MRR) and a photodetector,both of wh...We demonstrate a silicon-based microwave photonic filter(MPF) with flattop passband and adjustable bandwidth. The proposed MPF is realized by using a 10 th-order microring resonator(MRR) and a photodetector,both of which are integrated on a photonic chip. The full width at half-maximum(FWHM) bandwidth of the optical filter achieved at the drop port of the 10 th-order MRR is 21.6 GHz. The ripple of the passband is less than 0.3 dB, while the rejection ratio is 32 dB. By adjusting the deviation of the optical carrier wavelength from the center wavelength of the optical bandpass filter, the bandwidth of the MPF can be greatly changed. In the experiment, the FWHM bandwidth of the proposed MPF is tuned from 5.3 to 19.5 GHz, and the rejection ratio is higher than 30 dB.展开更多
Bloch oscillations(BOs),an important transport phenomenon,have been studied extensively in static systems but remain mysterious in Floquet systems.Here,by harnessing notions from photonic analogy,we propose a generali...Bloch oscillations(BOs),an important transport phenomenon,have been studied extensively in static systems but remain mysterious in Floquet systems.Here,by harnessing notions from photonic analogy,we propose a generalization of the existing BOs in photonic Floquet lattices,namely the“photonic Floquet–Bloch oscillations”,which refer to rescaled photonic Bloch oscillations with a period of extended least common multiple of the modulation period and the Bloch oscillation period.Next,we report the first visual observation of such photonic Floquet–Bloch oscillations(FBOs)by employing waveguide fluorescence microscopy.Most significantly,the FBOs surpass the existing BOs in Floquet systems and exhibit exotic properties on their own,including fractal spectrum and fractional Floquet tunneling.This new transport mechanism offers an intriguing method of wave manipulation that may contribute to rapidly developing fields in photonics,condensed matter physics,and quantum physics.展开更多
We propose and demonstrate a sensitive vector twist sensor based on a small period long period fiber grating(SP-LPFG)fabricated with a femtosecond(fs)laser.The fabricated SP-LPFG is compact in size(2.8 mm)and shows st...We propose and demonstrate a sensitive vector twist sensor based on a small period long period fiber grating(SP-LPFG)fabricated with a femtosecond(fs)laser.The fabricated SP-LPFG is compact in size(2.8 mm)and shows strong polarization dependent peaks in its transmission spectrum due to the vectorial behavior of high-order cladding modes.Twist sensing is realized by monitoring the polarization dependent peaks,since the polarization of input light changes with fiber twist.The proposed sensor can be interrogated by the peak intensity and wavelength,with high twist sensitivity that reaches 0.257 dB/deg and 0.115 nm/deg,respectively.展开更多
基金supported by the National Key R&D Program of China(Grant No.2023YFE0105800)the National Natural Science Foundation of China(Grant Nos.62275093 and 61775074)the Key R&D Program of Hubei Province(Grant No.2021BAA036).
文摘Random fiber lasers(RFLs)have attracted extensive attention due to their rich physical properties and wide applications.Here,a RFL using a cascaded fiber loop mirror(CFLM)is proposed and presented.A CFLM with 10 fiber loop mirrors(FLMs)is simulated by the transfer matrix method and used to provide random feedback.Multiple spikes are observed in both the simulated and measured reflection spectra.The RFL operates in a single longitudinal mode near the threshold and a time-varying multilongitudinal mode at higher pump powers.The RFL exhibits a time-varying radio-frequency spectrum.The Lévy–Gaussian distribution transition is observed,as in many RFLs.The operation mechanism of the lasing longitudinal modes and the impact of complex mode competition and mode hopping on the output characteristics are discussed through experimental and theoretical results.In this study,we unveil an artificial random feedback structure and pave another way for the realization of RFLs,which should be a platform for multidisciplinary studies in complex systems.
基金National Key Research and Development Program of China(2023YFE0105800)National Natural Science Foundation of China(62275084,62275093,62125503)Natural Science Foundation of Hubei Province(2023AFA028).
文摘Artificially designed hyperbolic metamaterials(HMMs)with extraordinary optical anisotropy can support highly sensitive plasmonic sensing detections,showcasing significant potential for advancements in medical research and clinical diagnostics.In this study,we develop a gold nanoridge HMM and disclose the plasmonic sensing physical mechanism based on this type ofHMMthrough theoretical and experimental studies.We determine that the high modal group velocity of plasmonic guided modes stemming from a large transverse permittivity of HMMs directly results in high sensitivity.By combining electron-beam lithography,oxygen plasma etching,and electroplating,the fabricated gold nanoridge array possesses an extremely high structural filling ratio that is difficult to obtain through conventional processes.This leads to a large transverse permittivity and enables highly confined and ultra-sensitive bulk plasmon-polariton(BPP)guided modes.By exciting these modes in the visible to near-infrared region,we achieve a record sensitivity of 53,300 nm/RIU and a figure of merit of 533.Furthermore,the developed plasmonic nanoridge HMM sensor exhibits an enhanced sensitivity of two orders of magnitude compared to that of the same type of HMM sensor in label-free biomolecule detection.Our study not only offers a promising avenue for label-free biosensing but also holds great potential to enhance early disease detection and monitoring.
基金National Natural Science Foundation of China(NSFC)(11664009,61501194)Natural Science Fund for Distinguished Young Scholars(61125501)+2 种基金Natural Science Foundation of Hubei Province(2014CFA004,2015CFB231,2016CFB370)Fundamental Research Funds for the Central Universities(HUST:2016YXMS025)Director Fund of Wuhan National Laboratory for Optoelectronics(WNLO)
文摘We demonstrate a silicon-based microwave photonic filter(MPF) with flattop passband and adjustable bandwidth. The proposed MPF is realized by using a 10 th-order microring resonator(MRR) and a photodetector,both of which are integrated on a photonic chip. The full width at half-maximum(FWHM) bandwidth of the optical filter achieved at the drop port of the 10 th-order MRR is 21.6 GHz. The ripple of the passband is less than 0.3 dB, while the rejection ratio is 32 dB. By adjusting the deviation of the optical carrier wavelength from the center wavelength of the optical bandpass filter, the bandwidth of the MPF can be greatly changed. In the experiment, the FWHM bandwidth of the proposed MPF is tuned from 5.3 to 19.5 GHz, and the rejection ratio is higher than 30 dB.
基金the National Key Research and Development Program of China(2023YFE0105800)the National Natural Science Foundation of China(62275093)+1 种基金the Research Grants Council of Hong Kong(No.14209519,C4050-21E)The Chinese University of Hong Kong(Group Research Scheme).
文摘Bloch oscillations(BOs),an important transport phenomenon,have been studied extensively in static systems but remain mysterious in Floquet systems.Here,by harnessing notions from photonic analogy,we propose a generalization of the existing BOs in photonic Floquet lattices,namely the“photonic Floquet–Bloch oscillations”,which refer to rescaled photonic Bloch oscillations with a period of extended least common multiple of the modulation period and the Bloch oscillation period.Next,we report the first visual observation of such photonic Floquet–Bloch oscillations(FBOs)by employing waveguide fluorescence microscopy.Most significantly,the FBOs surpass the existing BOs in Floquet systems and exhibit exotic properties on their own,including fractal spectrum and fractional Floquet tunneling.This new transport mechanism offers an intriguing method of wave manipulation that may contribute to rapidly developing fields in photonics,condensed matter physics,and quantum physics.
基金supported by the National Natural Science Foundation of China (Nos. 11574070, 11874126, and 51803037)the Leading Talents of Guangdong Province Program (No. 2016LJ06D506)the Natural Science FoundationofGuangdongProvince,China(No. 2019A1515011229)
文摘We propose and demonstrate a sensitive vector twist sensor based on a small period long period fiber grating(SP-LPFG)fabricated with a femtosecond(fs)laser.The fabricated SP-LPFG is compact in size(2.8 mm)and shows strong polarization dependent peaks in its transmission spectrum due to the vectorial behavior of high-order cladding modes.Twist sensing is realized by monitoring the polarization dependent peaks,since the polarization of input light changes with fiber twist.The proposed sensor can be interrogated by the peak intensity and wavelength,with high twist sensitivity that reaches 0.257 dB/deg and 0.115 nm/deg,respectively.
