查看更多>>摘要：Isotope shifts among different isotopes can be effectively addressed using narrow-linewidth lasers,facilitating laser iso-tope separation and achieving significant enrichment at a single stage.The separation of potassium isotopes,employing optical pumping and magnetic deflection,has proven to be efficient.To further improve the enrichment of 40K,we introduce 2D transverse cooling to minimize the divergence angle.Through this modification,we demonstrate enrichment of 40K,elevating it from 0.012％to 12％-20％.This represents an enrichment increase by three orders of magnitude,surpassing our previous result by one order.Our method is particularly well-suited for isotope enrichment of elements with extremely low abundance.
查看更多>>摘要：The suppression of polarization cross talk in lead zirconate titanate phase modulators as a key error source has been challenging for open-loop fiber optic gyroscopes[FOGs].We developed a polarization-diversity optical frequency domain reflectometry[OFDR]to measure the distributed modulation polarization error in the modulator.The error contributes 8 x 10-6 rad to FOG's bias instability.Using a UV-fabricated in-fiber λ/4 wave plate and polarization-mode converter with fiber taper technology,the modulation error has been suppressed by 15 dB in assembled FOGs.This approach reduced error with temperature from 25°/h to 0.7°/h,meeting the requirements of control-level gyroscopes with bias errors less than 1°/h.
查看更多>>摘要：We propose a transfer-learning multi-input multi-output[TL-MIMO]scheme to significantly reduce the required training com-plexity for converging the equalizers in mode-division multiplexing[MDM]systems.Based on a built three-mode[LP01,LP11a,and LP11b]multiplexed experimental system,we thoughtfully investigate the TL-MIMO performances on the three-typed data,collecting from different sampling times,launching optical powers,and inputting optical signal-to-noise ratios[OSNRs].A dramatic reduction of approximately 40％-83.33％in the required training complexity is achieved in all three scenarios.Furthermore,the good stability of TL-MIMO in both the launched powers and OSNR test bands has also been proved.
查看更多>>摘要：A large field of view is in high demand for disease diagnosis in clinical applications of optical coherence tomography[OCT]and OCT angiography[OCTA]imaging.Due to limits on the optical scanning range,the scanning speed,or the data process-ing speed,only a relatively small region could be acquired and processed for most of the current clinical OCT systems at one time and could generate a mosaic image of multiple adjacent small-region images with registration algorithms for disease analysis.In this work,we investigated performing cross-correlation[instead of phase-correlation]in the workflow of the Fourier-Mellin transform[FMT]method[called dual-cross-correlation-based translation and rotation registration,DCCTRR]for calculating translation and orientation offsets and compared its performance to the FMT method used on OCTA images alignment.Both phantom and in vivo experiments were implemented for comparisons,and the results quantitatively dem-onstrate that DCCTRR can align OCTA images with a lower overlap rate,which could improve the scanning efficiency of large-scale imaging in clinical applications.
查看更多>>摘要：In this work,we propose a method using frequency-modulated continuous-wave[FMCW]self-mixing interferometry[SMI]and all-phase fast Fourier transform[APFFT]for simultaneous measurement of speed and distance.APFFT offers superior accuracy in frequency determination by mitigating issues like the fence effect and spectrum leakage,contributing to the high-accuracy measurement for speed and distance.Both simulations and experiments have demonstrated relative errors at the levels of 10-4 and 10-3 for distance and speed measurements,respectively.Furthermore,factors impacting mea-surement performance have been discussed.The proposed method provides a high-performance and cost-effective sol-ution for distance and speed measurements,applicable across scientific research and various industrial domains.
查看更多>>摘要：Optical phased arrays[OPAs]have broad application prospects due to their advanced capability in beamforming and steer-ing.In this work,we achieve independent dual beams in the far field by dividing the array elements of the OPA,with the maximum scanning range reaching 100°.Based on the working principle of OPAs,theoretical considerations of such multi-beam generation are presented.A phase data allocation approach for OPAs in the presence of fabrication-induced random phase variation is developed.Simulations of large ensembles of OPAs with various levels of random residual phase errors have been conducted to help analyze the results.This approach can help OPAs realize multi-beams for light detection and ranging[LiDAR].
查看更多>>摘要：A 2 × 3 kW-level bidirectional output fiber oscillator is realized by combining the specially designed spindle-shaped ytterbium-doped fiber,non-wavelength-stabilized 976-nm LDs,and grating bandwidth optimization to balance transverse mode instability and stimulated Raman scattering.The maximum output powers at both ends are 3265 and 2840 W,respec-tively,with a total efficiency of 73.2％.The M2 factors of the lasers at both ends are about 1.98 and 2.38,respectively.The beam profile at both ends shows that a bidirectional output annular beam fiber oscillator has been realized,which has great potential in practical applications.
查看更多>>摘要：We demonstrate an all-polarization-maintaining[APM]fiber mode-locked laser based on nonlinear polarization evolution[NPE].A well-designed Sagnac fiber loop is employed to establish the nonlinear polarization evolution process in a polari-zation beam splitter[PBS]figure-8 fiber laser.Nonlinear loss curves are calculated to verify the saturable absorption char-acteristic of this NPE-based APM oscillator.Then,we simulate the pulse propagation process in the cavity to demonstrate the pulse mode-locked formation.Finally,we also design a realizable compact scheme to further reduce noise disturbances,achieving a 101-fs mode-locked pulse train with a 0.3-mrad integrated phase noise and a 0.006％integrated relative intensity noise[RIN].This figure-8 fiber laser provides a new scheme for compacting low-noise compact APM fiber lasers based on the NPE mode-locked mechanism.
查看更多>>摘要：Soliton generation schemes have attracted considerable scholarly attention.This paper introduces a novel backward tuning method for the reversible generation of dissipative Kerr solitons[DKSs].Reversible soliton generation relies on the thermal stabilization of the auxiliary laser,coupled with backward tuning of the pump laser,significantly increasing the range of soliton steps by over 10 times.Moreover,the method alleviates the stringent auxiliary laser detuning requirement.By adjusting the detuning of the auxiliary laser,diverse numbers of solitons can be deterministically generated,enhancing both flexibility and precision.
查看更多>>摘要：Electron-trapping materials,due to their exceptional ability of energy storage and controllable photon release under exter-nal stimulation,have attracted considerable attention in the field of optical information storage[OIS].In this work,Gd3Al3Ga2O12∶Ce3+,Yb3+fluorescent ceramics,were developed using air and vacuum sintering technology.By co-doping Ce3+and Yb3+,the trap density was significantly increased by 7.5 times compared to samples containing only Ce3+.Vacuum annealing further enhanced trap density by 1.6 times compared to samples sintered solely in air,while generating deep traps[1.44 eV],making Gd3Al3Ga2O12∶Ce3+,Yb3+an excellent OIS medium.This work is expected to facilitate the develop-ment of OIS materials.
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