查看更多>>摘要：Advanced imaging techniques have been widely used in various biological studies.Currently,numerous imaging modali-ties are utilized in biological applications,including medical imaging,diagnosis,biometrics,and fundamental biological research.Consequently,the demand for faster,clearer,and more accurate imaging techniques to support sophisticated biological studies has increased.However,there is a limitation in enhancing performance of imaging devices owing to the system complexity associated with bulky conventional optical elements.To address this issue,metasurfaces,which are flat and compact optical elements,have been considered potential candidates for biological imaging.Here,we compre-hensively discuss the metasurface empowered various imaging applications in biology,including their working principles and design strategies.Furthermore,we compared conventional imaging modalities with the metasurface-based imaging system.Finally,we discuss the current challenges and offer future perspectives on metasurfaces.
查看更多>>摘要：Artificial intelligence(AI)plays a critical role in signal recognition of distributed sensor systems(DSS),boosting its appli-cations in multiple monitoring fields.Due to the domain differences between massive sensors in signal acquisition condi-tions,such as manufacturing process,deployment,and environments,current AI schemes for signal recognition of DSS frequently encounter poor generalization performance.In this paper,an adaptive decentralized artificial intelligence(ADAI)method for signal recognition of DSS is proposed,to improve the entire generalization performance.By fine-tun-ing pre-trained model with the unlabeled data in each domain,the ADAI scheme can train a series of adaptive AI models for all target domains,significantly reducing the false alarm rate(FAR)and missing alarm rate(MAR)induced by domain differences.The field tests about intrusion signal recognition with distributed optical fiber sensors system demonstrate the efficacy of the ADAI scheme,showcasing a FAR of merely 4.3%and 0%,along with a MAR of only 1.4%and 2.7%within two specific target domains.The ADAI scheme is expected to offer a practical paradigm for signal recognition of DSS in multiple application fields.
查看更多>>摘要：Light beams carrying multiple orbital angular momentum(OAM)states,which can be realized by the structured media with phase singularities,have attracted great attentions in the fields of high dimensional optical information processing.Alternatively,a simple uniaxial crystal can be used to simultaneously generate four OAM states of light through the sec-ond harmonic generation and cascaded optical spin-orbit interaction(SOI)processes.However,two of the OAM states realized in the crystal are very weak and limit the practical applications.Here,we aim to circumvent this constraint by us-ing the sequential optical SOI processes in two crystals with threefold rotational symmetry.Four angular momentum states of the fundamental waves are prepared after the first crystal and then are utilized to generate the corresponding second harmonic waves(SHWs)with opposite spin and doubled OAM in the second crystal.Further through a sequen-tial SOI process,totally eight angular momentum states of the SHWs with nearly equal energy are experimentally ob-served.The proposed methodology may find potential applications in optical communications,parallel optical computing,optical manipulation and so on.
查看更多>>摘要：The specific detection of tumor markers is crucial in early tumor screening and subsequent treatment processes.To ac-curately distinguish the signal response caused by trace markers,the high demodulation resolution of the sensor is nec-essary.In this paper,we propose a dual-wavelength fiber laser sensing system enhanced with microwave photonics de-modulation technology to achieve high-resolution tumor marker detection.This sensing system can simultaneously per-form spectral wavelength-domain and frequency-domain analyses.Experimental results demonstrate that this system's refractive index(RI)sensitivity reaches 1083 nm/RIU by wavelength analysis and-1902 GHz/RIU by frequency analysis,with ideal detection resolutions of 1.85×10-5 RIU and 5.26×10-8 RIU,respectively.Compared with traditional wavelength domain analysis,the demodulation resolution is improved by three orders of magnitude,based on the same sensing structure.To validate its biosensing performance,carcinoembryonic antigen-related cell adhesion molecule 5(CEACAM5)is selected as the detection target.Experimental results show that the improved sensing system has a limit of detection(LOD)of 0.076 ng/mL and a detection resolution of 0.008 ng/mL.Experimental results obtained from human serum samples are consistent with clinical data,highlighting the strong clinical application potential of the proposed sens-ing system and analysis method.
查看更多>>摘要：Intense vortex beam is expected to empower captivating phenomena and applications in high power laser-matter interac-tions.Currently,the superposition of multiple vortex beams has shown the unique ability to tailor and enhance the vortex field.However,traditional strategies to generate such beams suffer from large volume or/and low laser-induced damage threshold,hindering the practical widespread applications.Herein,a single high-threshold metasurface is proposed and experimentally demonstrated for the generation and superposition of multiple collinear vortex beams.This scheme takes advantage of the high conversion efficiency of phase-only modulation in the metasurface design by adopting the concept of a sliced phase pattern in the azimuthal direction.An optical hot spot with an enhanced intensity and steady spatial propagation is experimentally achieved.Moreover,femtosecond laser-induced birefringent nanostructures embedded in silica glass are utilized as the building block with high optical efficiency.Transmittance greater than 99.4%in the near-in-frared range and laser-induced damage threshold as high as 68.0 J/cm2(at 1064 nm,6 ns)are experimentally verified.Considering these remarkable performances,the demonstrated high-threshold metasurface has promising applications in a host of high-power laser fields.
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