A simple quasi-distributed fiber sensing interrogation system based on random speckles is proposed for weak fiber Bragg gratings(WFBGs) in this work. Without using tunable lasers or spectrometers, a piece of multimode...A simple quasi-distributed fiber sensing interrogation system based on random speckles is proposed for weak fiber Bragg gratings(WFBGs) in this work. Without using tunable lasers or spectrometers, a piece of multimode fiber is applied to interrogate the WFBGs relying on the wavelength sensitivity of speckles. Instead of the CCD sensor, an InGaAs quadrant detector serves as the receiver to capture the fast-changing speckle patterns. A supervised deep learning algorithm of the multilayer perceptron architecture is implemented to process speckle data and to interrogate temperature changes or dynamic strains. The proposed demodulation system is experimentally demonstrated for WFBGs with 0.1% reflectivity.The experimental results demonstrate that the new system is capable of measuring temperature change with an accuracy of 1℃ and achieving dynamic frequency of 100 Hz. This speckle-based interrogation system paves a new way for distributed WFBGs sensing with a simple design.展开更多
A cylindricalÖffner stretcher based on ternary reflector(COSTER)is proposed and analyzed.Compared with the traditionalÖffner stretcher,the COSTER has no off-axis aberration in the multipass configuration,and...A cylindricalÖffner stretcher based on ternary reflector(COSTER)is proposed and analyzed.Compared with the traditionalÖffner stretcher,the COSTER has no off-axis aberration in the multipass configuration,and the output laser of COSTER has lower spectral phase noise and higher temporal contrast in the far field.The COSTER is quite suitable to be used in multipetawatt laser facilities,and it might be the preferred stretcher configuration for ultrafast and ultra-intense lasers.展开更多
An adaptive microwave photonic angle-of-arrival(AOA) estimation approach based on a convolutional neural network with a bidirectional gated recurrent unit(BiGRU-CNN) is proposed and demonstrated.Compared with the prev...An adaptive microwave photonic angle-of-arrival(AOA) estimation approach based on a convolutional neural network with a bidirectional gated recurrent unit(BiGRU-CNN) is proposed and demonstrated.Compared with the previously reported AOA estimation methods based on phase-to-power mapping,the proposed method is unnecessary to know the frequency of the signal under test(SUT) in advance.The envelope voltage correlation matrix is obtained from dual-drive Mach–Zehnder modulator(N-DDMZM,N > 2) optical interferometer arrays first,and then AOA estimations are performed on different frequency signals with the aid of BiGRU-CNN.A three-DDMZM-based experiment is carried out to assess the estimation performance of microwave signals at three different frequencies,and the mean absolute error is only 0.1545°.展开更多
Chinese Optics Letters is a short-article journal for the rapid dissemination of new, important results in all branches of optical science and technology and related fields, published monthly by Chinese Laser Press an...Chinese Optics Letters is a short-article journal for the rapid dissemination of new, important results in all branches of optical science and technology and related fields, published monthly by Chinese Laser Press and distributed abroad by Optica Publishing Group.展开更多
The quantum key distribution(QKD)network is a promising solution for secure communications.In this paper,we proposed a polarization-independent phase-modulated polarization encoding module,and it can be combined with ...The quantum key distribution(QKD)network is a promising solution for secure communications.In this paper,we proposed a polarization-independent phase-modulated polarization encoding module,and it can be combined with a dense wavelength division multiplexer(DWDM)to achieve multi-user QKD.We experimentally test the encoding module with a repetition rate of 62.5 MHz,and its average quantum bit error rate(QBER)is as low as 0.4%.Finally,we implement a principle verification test for simultaneous QKD for 1 to 2 users in 100 min,and the average QBER of two users under the transmission distance of 1 km and 5 km is kept below 0.8%.Due to the use of polarization encoding,the module can also realize scalable network architecture in free-space QKD systems in the future.展开更多
We introduce a simple one-dimensional(1D)structure in the design of 1D color splitters(1D-CSs)with RGB unit cells for color imaging and propose a single-to-double-layer design in 1D-CSs.Based on inverse design metasur...We introduce a simple one-dimensional(1D)structure in the design of 1D color splitters(1D-CSs)with RGB unit cells for color imaging and propose a single-to-double-layer design in 1D-CSs.Based on inverse design metasurfaces,we demonstrate numerically a single-layer 1D-CS with a full-color efficiency of 46.2%and a double-layer 1D-CS with a full-color efficiency of48.2%;both of them are significantly higher than that of traditional color filters.Moreover,we demonstrate a 1D-CS that has application value by evaluating the double-layer 1D-CS’s performances in terms of incident angle sensitivity,polarization angle sensitivity,and assembly tolerance.展开更多
We demonstrate an ultra-compact short-wave infrared[SWIR]multispectral detector chip by monolithically integrating the narrowband Fabry–Perot microcavities array with the In Ga As detector focal plane array.A 16-chan...We demonstrate an ultra-compact short-wave infrared[SWIR]multispectral detector chip by monolithically integrating the narrowband Fabry–Perot microcavities array with the In Ga As detector focal plane array.A 16-channel SWIR multispectral detector has been fabricated for demonstration.Sixteen different narrowband response spectra are acquired on a 64×64 pixels detector chip by four times combinatorial etching processes.The peak of the response spectra varies from1450 to 1666 nm with full width at half-maximum of 24 nm on average.The size of the SWIR multispectral detection system is remarkably reduced to a 2 mm^(2) detector chip.展开更多
In this study,an excellent polarization optical crystal LiNa_(5)Mo_(9)O_(30) with wide transmission range and high laser damage threshold was researched in detail.The laser damage threshold of the LiNa_(5)Mo_(9)O_(30)...In this study,an excellent polarization optical crystal LiNa_(5)Mo_(9)O_(30) with wide transmission range and high laser damage threshold was researched in detail.The laser damage threshold of the LiNa_(5)Mo_(9)O_(30) crystal was measured to be 2.64GW/cm^(2),which was the highest among polarized optical crystals.The birefringence in the range of 0.435-5μm was larger than 0.14,while the wedge angle between 31.94°and 32.12°would satisfy the application in this waveband.The extinction ratio of the fabricated prism with the wedge angel of 31.09°was larger than 15,000:1.The results show that the LiNa_(5)Mo_(9)O_(30) prism is an excellent polarization device,especially in the mid-infrared range and high-power applications.展开更多
An active ultrafast formation and modulation of dual-band plasmon-induced transparency(PIT) effect is theoretically and experimentally studied in a novel metaphotonic device operating in the terahertz regime,for the f...An active ultrafast formation and modulation of dual-band plasmon-induced transparency(PIT) effect is theoretically and experimentally studied in a novel metaphotonic device operating in the terahertz regime,for the first time,to the best of our knowledge.Specifically,we designed and fabricated a triatomic metamaterial hybridized with silicon islands following a newly proposed modulating mechanism.In this mechanism,a localized surface plasmon resonance is induced by the broken symmetry of a C_(2)structure,acting as the quasi-dark mode.Excited by exterior laser pumps,the photo-induced carriers in silicon promote the quasi-dark mode,which shields the near-field coupling between the dark mode and bright mode supported by the triatomic metamaterial,leading to the dynamical modulation of terahertz waves from individual-band into dual-band PIT effects,with a decay constant of 493 ps.Moreover,a remarkable slow light effect occurs in the modulating process,accompanied by the dual-transparent windows.The dynamical switching technique of the dual-band PIT effect introduced in this work highlights the potential usefulness of this metaphotonic device in optical information processing and communication,including multi-frequency filtering,tunable sensors,and optical storage.展开更多
A new unsaturated wind-chime model is proposed for calculating the formation time of the diffraction rings induced by spatial self-phase modulation(SSPM) in molybdenum disulfide suspension.To optimize the traditional ...A new unsaturated wind-chime model is proposed for calculating the formation time of the diffraction rings induced by spatial self-phase modulation(SSPM) in molybdenum disulfide suspension.To optimize the traditional wind-chime model,the concentration variable of 2 D materials was introduced.The results of the unsaturated wind-chime model match quite well with the SSPM experimental results of molybdenum disulfide.Based on this model,the shortest formation time of diffraction rings and their corresponding concentration and light intensity can be predicted using limited data.Theoretically,by increasing the viscosity coefficient of the solution,the response time of the diffraction ring,to reach the maximum value,can be significantly reduced.It has advanced significance in shortening the response time of photonic diodes.展开更多
In this Letter, we present B-scan-sectioned dynamic micro-optical coherence tomography(BD-MOCT) for high-quality subcellular dynamic contrast imaging. Dynamic micro-optical coherence tomography(D-MOCT) is a functional...In this Letter, we present B-scan-sectioned dynamic micro-optical coherence tomography(BD-MOCT) for high-quality subcellular dynamic contrast imaging. Dynamic micro-optical coherence tomography(D-MOCT) is a functional optical coherence tomography(OCT) technique performed on high-resolution(micron level) OCT systems;hundreds of consecutive B-scans need to be acquired for dynamic signal extraction, which requires relatively long data acquisition time. Bulk motions occurring during data acquisition(even at the micron level) may degrade the quality of the obtained dynamic contrast images. In BD-MOCT, each full B-scan is divided into several sub-B-scans, and each sub-B-scan repeats multiple times before the sample beam moves to the next sub-B-scan. After all of the sub-B-scans for a full B-scan are completely acquired, we stitch all of the sub-B-scans into the same number of full B-scans. In this way, the time interval between two consecutive stitched B-scans could be reduced multiple times for bulk-motion suppression. The performed scanning protocol modulates the scanning sequences of fast scanning and repeat scanning for improving the dynamic contrast image quality, while the total data acquisition time remains almost the same.展开更多
We develop a low frequency fiber Fabry–Perot(F-P)seismometer based on transfer function analysis.The seismometer structure and demodulation system accuracy are limitations of low frequency seismic monitoring.The tran...We develop a low frequency fiber Fabry–Perot(F-P)seismometer based on transfer function analysis.The seismometer structure and demodulation system accuracy are limitations of low frequency seismic monitoring.The transfer function of the F-P seismometer is analyzed,and the mass displacement spectrum(MDS)is introduced.MDS provides guidance for mechanical structure design and optical interferometer analysis to achieve low noise.The F-P seismometer prototype is built.The experiment shows that the prototype has an average noise of 6.74 ng=p Hz below 50 Hz,and its noise is less than that of the global new high noise model within 0.16–50 Hz,whose potential is considerable.展开更多
Absorption induced by activated magnesium(Mg)in a p-type layer contributes considerable optical internal loss in Ga Nbased laser diodes(LDs).An LD structure with a distributed polarization doping(DPD)p-cladding layer(...Absorption induced by activated magnesium(Mg)in a p-type layer contributes considerable optical internal loss in Ga Nbased laser diodes(LDs).An LD structure with a distributed polarization doping(DPD)p-cladding layer(CL)without intentional Mg doping was designed and fabricated.The influence of the anti-waveguide structure on optical confinement was studied by optical simulation.The threshold current density,slope efficiency of LDs with DPD p-CL,and Mg-doped CL,respectively,were compared.It was found that LDs with DPD p-CL showed lower threshold current density but reduced slope efficiency,which were caused by decreasing internal loss and hole injection,respectively.展开更多
Chinese Optics Letters is a short-article journal for the rapid dissemination of new, important results in all branches of optical science and technology and related fields, published monthly by Chinese Laser Press an...Chinese Optics Letters is a short-article journal for the rapid dissemination of new, important results in all branches of optical science and technology and related fields, published monthly by Chinese Laser Press and distributed abroad by the Optical Society(OSA).展开更多
Chinese Optics Letters is a short-article journal for the rapid dissemination of new, important results in all branches of optical science and technology and related fields, published monthly by Chinese Laser Press an...Chinese Optics Letters is a short-article journal for the rapid dissemination of new, important results in all branches of optical science and technology and related fields, published monthly by Chinese Laser Press and distributed abroad by the Optical Society (OSA).展开更多
We propose and demonstrate the cascaded multi-wavelength mode-locked erbium-doped fiber laser(EDFL) based on ultralong-period gratings(ULPGs) for the first time, to the best of our knowledge.Study found that the ULPG ...We propose and demonstrate the cascaded multi-wavelength mode-locked erbium-doped fiber laser(EDFL) based on ultralong-period gratings(ULPGs) for the first time, to the best of our knowledge.Study found that the ULPG can be used as both a mode-locker for pulse shaping and a comb filter for multi-wavelength generation simultaneously.Using the dual-function of ULPG, three-, four-, five-, six-, and seven-wavelength mode-locked pulses are obtained in EDFL, seven of which are the largest number of wavelengths up to now.For the four-wavelength soliton pulses, their pulse width is about 7.8 ps.The maximum average output power and slope efficiency of these pulses are 8.4 m W and 2.03%, respectively.Besides the conventional pulses, hybrid soliton pulses composed of a four-wavelength pulse and single soliton are also observed.Finally, the effect of cavity dispersion on the multi-wavelength mode-locked pulses is also discussed.Our findings indicate that apart from common sensing and filtering, the ULPG may also possess attractive nonlinear pulse-shaping property for ultrafast photonics application.展开更多
We experimentally demonstrated that the distributed feedback(DFB) lasers with the active distributed reflector achieved a 25.8 Gb/s operation over a wide temperature range of -40 to 85℃. The DFB lasers can achieve ad...We experimentally demonstrated that the distributed feedback(DFB) lasers with the active distributed reflector achieved a 25.8 Gb/s operation over a wide temperature range of -40 to 85℃. The DFB lasers can achieve additional feedback from an active distributed reflector with accurately controlled phase, and single-mode yields are not related to the position of cleave. The threshold currents of the fabricated laser are 6 mA and 20 mA at -40℃ and 85℃, respectively. The side mode suppression ratio of the fabricated laser is above 50 dB at all temperatures. Transmissions of 25.8 Gb/s after 10 km single-mode fibers with clear eye openings and less than 0.8 dB power penalty over a wide temperature range have been demonstrated as well.展开更多
We propose a metalens for coaxial double wavelength focusing.One focusing spot is a circular solid spot,and the other focusing spot is a doughnut-shaped spot that is circling the solid spot.The designed metalens was c...We propose a metalens for coaxial double wavelength focusing.One focusing spot is a circular solid spot,and the other focusing spot is a doughnut-shaped spot that is circling the solid spot.The designed metalens was composed of a met a-molecular nanostructured cell array.Each meta-molecular nanostructured cell was divided into four squares.Two slots with exactly the same shape,but usually with the rotation angle measured clockwise from the positive x axis,are etched into the gold film in two diagonally connected squares.Another two slots with the same shape but with the rotation angle measured counter-clockwise from the positive x axis are etched into another two diagonally connected squares in the same cell.The lasers with two different wavelengths are trans?formed into right-handed and left-handed circularly polarized beams,respectively.The two sets of slots with different azimuthal rotations modulated the phases of incident right-handed and left-handed circularly polarized beams independently.The numerical simulation with finite-difference time-domain(FDTD)software was carried out,and the experimental verification was also implemented.Both the experimental result and the numerical simulation agree well with the theoretical design.展开更多
By controlling the wavelength and power of multiple light sources, we have realized a highly flexible Nyquist pulse generation scheme, in which the pulse repetition frequency, pulse multiplication factor, waveform env...By controlling the wavelength and power of multiple light sources, we have realized a highly flexible Nyquist pulse generation scheme, in which the pulse repetition frequency, pulse multiplication factor, waveform envelope shape, and duty cycle are all tunable. By modulating the 3.2 GHz RF signal, we experimentally generated Nyquist pulses with repetition rates of 6.4 GHz and 9.6 GHz, a rectangular wave with a duty cycle of 0.26,and a sawtooth wave with a duty cycle of 0.52.展开更多
Chinese Optics Letters is a short-article journal for the rapid dissemination of new,important results in all branches of optical science and technology and related fields,published monthly by Chinese Laser Press and ...Chinese Optics Letters is a short-article journal for the rapid dissemination of new,important results in all branches of optical science and technology and related fields,published monthly by Chinese Laser Press and distributed abroad by the Optical Society(OSA).Submission of Papers Authors must submit online:https://mc03.manuscriptcentral.com/clp-col.Electronic files of MS Word(recommended)and LaTeX are acceptable.Submission of a manuscript must be the original work of the author(s)and have not been published elsewhere or under consideration for another publication,or a substantially similar form in any language.展开更多
基金supported by the National Key Research and Development Program of China(No.2021YFC3340400)Key Laboratory of Medical Electronics and Digital Health of Zhejiang Province(No.MEDH202209)+1 种基金Natural Science Foundation of Zhejiang Province(No.LY22F050004)Zhejiang Xinmiao Talents Program(No.2022R409043).
文摘A simple quasi-distributed fiber sensing interrogation system based on random speckles is proposed for weak fiber Bragg gratings(WFBGs) in this work. Without using tunable lasers or spectrometers, a piece of multimode fiber is applied to interrogate the WFBGs relying on the wavelength sensitivity of speckles. Instead of the CCD sensor, an InGaAs quadrant detector serves as the receiver to capture the fast-changing speckle patterns. A supervised deep learning algorithm of the multilayer perceptron architecture is implemented to process speckle data and to interrogate temperature changes or dynamic strains. The proposed demodulation system is experimentally demonstrated for WFBGs with 0.1% reflectivity.The experimental results demonstrate that the new system is capable of measuring temperature change with an accuracy of 1℃ and achieving dynamic frequency of 100 Hz. This speckle-based interrogation system paves a new way for distributed WFBGs sensing with a simple design.
基金supported by the Innovation and Development Foundation of China Academy of Engineering Physics(No.CX20200022)the Science and Technology on Plasma Physics Laboratory Independent Research Projects of China Academy of Engineering Physics(No.JCKYS2022212004)。
文摘A cylindricalÖffner stretcher based on ternary reflector(COSTER)is proposed and analyzed.Compared with the traditionalÖffner stretcher,the COSTER has no off-axis aberration in the multipass configuration,and the output laser of COSTER has lower spectral phase noise and higher temporal contrast in the far field.The COSTER is quite suitable to be used in multipetawatt laser facilities,and it might be the preferred stretcher configuration for ultrafast and ultra-intense lasers.
基金supported by the National Natural Science Foundation of China (Nos.61801498 and 62075240)the National Key Research and Development Program of China (No.2020YFB2205804)。
文摘An adaptive microwave photonic angle-of-arrival(AOA) estimation approach based on a convolutional neural network with a bidirectional gated recurrent unit(BiGRU-CNN) is proposed and demonstrated.Compared with the previously reported AOA estimation methods based on phase-to-power mapping,the proposed method is unnecessary to know the frequency of the signal under test(SUT) in advance.The envelope voltage correlation matrix is obtained from dual-drive Mach–Zehnder modulator(N-DDMZM,N > 2) optical interferometer arrays first,and then AOA estimations are performed on different frequency signals with the aid of BiGRU-CNN.A three-DDMZM-based experiment is carried out to assess the estimation performance of microwave signals at three different frequencies,and the mean absolute error is only 0.1545°.
文摘Chinese Optics Letters is a short-article journal for the rapid dissemination of new, important results in all branches of optical science and technology and related fields, published monthly by Chinese Laser Press and distributed abroad by Optica Publishing Group.
基金supported by the National Natural Science Foundation of China(Nos.61771205 and 62071186)Natural Science Foundation of Guangdong Province(No.2015A030313388)+1 种基金Science and Technology Planning Project of Guangdong Province(Nos.2015B010128012 and 2017KZ010101)Key Laboratory Foundation of Guangdong Province,China(No.2020B1212060066)。
文摘The quantum key distribution(QKD)network is a promising solution for secure communications.In this paper,we proposed a polarization-independent phase-modulated polarization encoding module,and it can be combined with a dense wavelength division multiplexer(DWDM)to achieve multi-user QKD.We experimentally test the encoding module with a repetition rate of 62.5 MHz,and its average quantum bit error rate(QBER)is as low as 0.4%.Finally,we implement a principle verification test for simultaneous QKD for 1 to 2 users in 100 min,and the average QBER of two users under the transmission distance of 1 km and 5 km is kept below 0.8%.Due to the use of polarization encoding,the module can also realize scalable network architecture in free-space QKD systems in the future.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030009)National Natural Science Foundation of China(Nos.61935013,61975133,and 11947017)+2 种基金Natural Science Foundation of Guangdong Province(No.2020A1515011185)Science and Technology Innovation Commission of Shenzhen,Shenzhen Peacock Plan(Nos.KQJSCX20170727100838364,KQTD20170330110444030,ZDSYS201703031605029,and JCYJ20200109114018750)Shenzhen University(No.2019075)。
文摘We introduce a simple one-dimensional(1D)structure in the design of 1D color splitters(1D-CSs)with RGB unit cells for color imaging and propose a single-to-double-layer design in 1D-CSs.Based on inverse design metasurfaces,we demonstrate numerically a single-layer 1D-CS with a full-color efficiency of 46.2%and a double-layer 1D-CS with a full-color efficiency of48.2%;both of them are significantly higher than that of traditional color filters.Moreover,we demonstrate a 1D-CS that has application value by evaluating the double-layer 1D-CS’s performances in terms of incident angle sensitivity,polarization angle sensitivity,and assembly tolerance.
基金supported by the National Natural Science Foundation of China(NSFC)(No.11874376)Shanghai Science and Technology Foundations(Nos.19DZ2293400 and 19ZR1465900)+1 种基金Shanghai Municipal Science and Technology Major Project(No.2019SHZDZX01)Chinese Academy of Sciences President’s International Fellowship Initiative(No.2021PT0007)。
文摘We demonstrate an ultra-compact short-wave infrared[SWIR]multispectral detector chip by monolithically integrating the narrowband Fabry–Perot microcavities array with the In Ga As detector focal plane array.A 16-channel SWIR multispectral detector has been fabricated for demonstration.Sixteen different narrowband response spectra are acquired on a 64×64 pixels detector chip by four times combinatorial etching processes.The peak of the response spectra varies from1450 to 1666 nm with full width at half-maximum of 24 nm on average.The size of the SWIR multispectral detection system is remarkably reduced to a 2 mm^(2) detector chip.
基金This work was supported by the National Natural Science Foundation of China(Nos.51021062,62175129,50990061,and 50802054)973 Program of China(No.2010CB630702)+1 种基金China Postdoctoral Science Foundation(No.20110491600)Program of Introducing Talents of Disciplines to Universities in China(111 Program)(No.b06017).
文摘In this study,an excellent polarization optical crystal LiNa_(5)Mo_(9)O_(30) with wide transmission range and high laser damage threshold was researched in detail.The laser damage threshold of the LiNa_(5)Mo_(9)O_(30) crystal was measured to be 2.64GW/cm^(2),which was the highest among polarized optical crystals.The birefringence in the range of 0.435-5μm was larger than 0.14,while the wedge angle between 31.94°and 32.12°would satisfy the application in this waveband.The extinction ratio of the fabricated prism with the wedge angel of 31.09°was larger than 15,000:1.The results show that the LiNa_(5)Mo_(9)O_(30) prism is an excellent polarization device,especially in the mid-infrared range and high-power applications.
基金supported by the National Natural Science Foundation of China (Nos. 11804387, 11802339, 11805276, 11902358, 61805282, and 61801498)the Scientific Researches Foundation of National University of Defense Technology (Nos. ZK18-03-22, ZK18-01-03, and ZK18-03-36)the Science Fund for Distinguished Young Scholars of Hunan Province (No. 2020JJ2036)
文摘An active ultrafast formation and modulation of dual-band plasmon-induced transparency(PIT) effect is theoretically and experimentally studied in a novel metaphotonic device operating in the terahertz regime,for the first time,to the best of our knowledge.Specifically,we designed and fabricated a triatomic metamaterial hybridized with silicon islands following a newly proposed modulating mechanism.In this mechanism,a localized surface plasmon resonance is induced by the broken symmetry of a C_(2)structure,acting as the quasi-dark mode.Excited by exterior laser pumps,the photo-induced carriers in silicon promote the quasi-dark mode,which shields the near-field coupling between the dark mode and bright mode supported by the triatomic metamaterial,leading to the dynamical modulation of terahertz waves from individual-band into dual-band PIT effects,with a decay constant of 493 ps.Moreover,a remarkable slow light effect occurs in the modulating process,accompanied by the dual-transparent windows.The dynamical switching technique of the dual-band PIT effect introduced in this work highlights the potential usefulness of this metaphotonic device in optical information processing and communication,including multi-frequency filtering,tunable sensors,and optical storage.
基金financially supported by the National Natural Science Foundation of China (Nos. 61875232, 61874141, and 11904239)the China Postdoctoral Science Foundation (No. 2021M690169)
文摘A new unsaturated wind-chime model is proposed for calculating the formation time of the diffraction rings induced by spatial self-phase modulation(SSPM) in molybdenum disulfide suspension.To optimize the traditional wind-chime model,the concentration variable of 2 D materials was introduced.The results of the unsaturated wind-chime model match quite well with the SSPM experimental results of molybdenum disulfide.Based on this model,the shortest formation time of diffraction rings and their corresponding concentration and light intensity can be predicted using limited data.Theoretically,by increasing the viscosity coefficient of the solution,the response time of the diffraction ring,to reach the maximum value,can be significantly reduced.It has advanced significance in shortening the response time of photonic diodes.
基金This work was supported by the Natural Science Foundation of Jiangsu Province(No.BK20210227).
文摘In this Letter, we present B-scan-sectioned dynamic micro-optical coherence tomography(BD-MOCT) for high-quality subcellular dynamic contrast imaging. Dynamic micro-optical coherence tomography(D-MOCT) is a functional optical coherence tomography(OCT) technique performed on high-resolution(micron level) OCT systems;hundreds of consecutive B-scans need to be acquired for dynamic signal extraction, which requires relatively long data acquisition time. Bulk motions occurring during data acquisition(even at the micron level) may degrade the quality of the obtained dynamic contrast images. In BD-MOCT, each full B-scan is divided into several sub-B-scans, and each sub-B-scan repeats multiple times before the sample beam moves to the next sub-B-scan. After all of the sub-B-scans for a full B-scan are completely acquired, we stitch all of the sub-B-scans into the same number of full B-scans. In this way, the time interval between two consecutive stitched B-scans could be reduced multiple times for bulk-motion suppression. The performed scanning protocol modulates the scanning sequences of fast scanning and repeat scanning for improving the dynamic contrast image quality, while the total data acquisition time remains almost the same.
基金the National Key R&D Program of China(No.2019YFC1509500)Shenzhen Science and Technology Program(No.KQTD20180412181337494)+2 种基金National Natural Science Foundation of China(NSFC)(No.U1939207)Scientific Instrument Developing Project of the Chinese Academy ofSciences,Youth Innovation Promotion Association of CAS(No.2016106)Strategic Priority Research Program A of the Chinese Academy ofSciences(No.XDA22010201)。
文摘We develop a low frequency fiber Fabry–Perot(F-P)seismometer based on transfer function analysis.The seismometer structure and demodulation system accuracy are limitations of low frequency seismic monitoring.The transfer function of the F-P seismometer is analyzed,and the mass displacement spectrum(MDS)is introduced.MDS provides guidance for mechanical structure design and optical interferometer analysis to achieve low noise.The F-P seismometer prototype is built.The experiment shows that the prototype has an average noise of 6.74 ng=p Hz below 50 Hz,and its noise is less than that of the global new high noise model within 0.16–50 Hz,whose potential is considerable.
基金supported by the National Natural Science Foundation of China(Nos.61834008,61574160,6180416461704184)+2 种基金National Key Research and Development Program of China(Nos.2017YFE0131500 and2017YFB0405000)Natural Science Foundation of Jiangsu Province(No.BK20180254)China Postdoctoral Science Foundation(No.2018M630619)。
文摘Absorption induced by activated magnesium(Mg)in a p-type layer contributes considerable optical internal loss in Ga Nbased laser diodes(LDs).An LD structure with a distributed polarization doping(DPD)p-cladding layer(CL)without intentional Mg doping was designed and fabricated.The influence of the anti-waveguide structure on optical confinement was studied by optical simulation.The threshold current density,slope efficiency of LDs with DPD p-CL,and Mg-doped CL,respectively,were compared.It was found that LDs with DPD p-CL showed lower threshold current density but reduced slope efficiency,which were caused by decreasing internal loss and hole injection,respectively.
文摘Chinese Optics Letters is a short-article journal for the rapid dissemination of new, important results in all branches of optical science and technology and related fields, published monthly by Chinese Laser Press and distributed abroad by the Optical Society(OSA).
文摘Chinese Optics Letters is a short-article journal for the rapid dissemination of new, important results in all branches of optical science and technology and related fields, published monthly by Chinese Laser Press and distributed abroad by the Optical Society (OSA).
基金supported by the Natural Science Foundation of Heilongjiang Province (No.JJ2019LH1509)National Natural Science Foundation of China (NSFC)(Nos.11704086 and61875043)+1 种基金Fundamental Research Funds for the Central Universities (No.3072020CF2519)111 Project of Harbin Engineering University (No.B13015)。
文摘We propose and demonstrate the cascaded multi-wavelength mode-locked erbium-doped fiber laser(EDFL) based on ultralong-period gratings(ULPGs) for the first time, to the best of our knowledge.Study found that the ULPG can be used as both a mode-locker for pulse shaping and a comb filter for multi-wavelength generation simultaneously.Using the dual-function of ULPG, three-, four-, five-, six-, and seven-wavelength mode-locked pulses are obtained in EDFL, seven of which are the largest number of wavelengths up to now.For the four-wavelength soliton pulses, their pulse width is about 7.8 ps.The maximum average output power and slope efficiency of these pulses are 8.4 m W and 2.03%, respectively.Besides the conventional pulses, hybrid soliton pulses composed of a four-wavelength pulse and single soliton are also observed.Finally, the effect of cavity dispersion on the multi-wavelength mode-locked pulses is also discussed.Our findings indicate that apart from common sensing and filtering, the ULPG may also possess attractive nonlinear pulse-shaping property for ultrafast photonics application.
文摘We experimentally demonstrated that the distributed feedback(DFB) lasers with the active distributed reflector achieved a 25.8 Gb/s operation over a wide temperature range of -40 to 85℃. The DFB lasers can achieve additional feedback from an active distributed reflector with accurately controlled phase, and single-mode yields are not related to the position of cleave. The threshold currents of the fabricated laser are 6 mA and 20 mA at -40℃ and 85℃, respectively. The side mode suppression ratio of the fabricated laser is above 50 dB at all temperatures. Transmissions of 25.8 Gb/s after 10 km single-mode fibers with clear eye openings and less than 0.8 dB power penalty over a wide temperature range have been demonstrated as well.
基金supported by the National Natural Science Foundation of China(Nos.61675093,61775140,and 61905106)the Natural Science Foundation of Shandong Province(Nos.ZR2017MA035 and ZR2019PF013)。
文摘We propose a metalens for coaxial double wavelength focusing.One focusing spot is a circular solid spot,and the other focusing spot is a doughnut-shaped spot that is circling the solid spot.The designed metalens was composed of a met a-molecular nanostructured cell array.Each meta-molecular nanostructured cell was divided into four squares.Two slots with exactly the same shape,but usually with the rotation angle measured clockwise from the positive x axis,are etched into the gold film in two diagonally connected squares.Another two slots with the same shape but with the rotation angle measured counter-clockwise from the positive x axis are etched into another two diagonally connected squares in the same cell.The lasers with two different wavelengths are trans?formed into right-handed and left-handed circularly polarized beams,respectively.The two sets of slots with different azimuthal rotations modulated the phases of incident right-handed and left-handed circularly polarized beams independently.The numerical simulation with finite-difference time-domain(FDTD)software was carried out,and the experimental verification was also implemented.Both the experimental result and the numerical simulation agree well with the theoretical design.
基金partially supported by the National Natural Science Foundation of China(NSFC)(Nos.61922056,61875122,and 61535006)
文摘By controlling the wavelength and power of multiple light sources, we have realized a highly flexible Nyquist pulse generation scheme, in which the pulse repetition frequency, pulse multiplication factor, waveform envelope shape, and duty cycle are all tunable. By modulating the 3.2 GHz RF signal, we experimentally generated Nyquist pulses with repetition rates of 6.4 GHz and 9.6 GHz, a rectangular wave with a duty cycle of 0.26,and a sawtooth wave with a duty cycle of 0.52.
文摘Chinese Optics Letters is a short-article journal for the rapid dissemination of new,important results in all branches of optical science and technology and related fields,published monthly by Chinese Laser Press and distributed abroad by the Optical Society(OSA).Submission of Papers Authors must submit online:https://mc03.manuscriptcentral.com/clp-col.Electronic files of MS Word(recommended)and LaTeX are acceptable.Submission of a manuscript must be the original work of the author(s)and have not been published elsewhere or under consideration for another publication,or a substantially similar form in any language.
