We report the characterization of the pump absorption and emission dynamic properties of a Tm:Lu2O3 ceramic lasing medium using a three-mirror folded laser cavity.We measured a slope efficiency of 73%,which allowed us...We report the characterization of the pump absorption and emission dynamic properties of a Tm:Lu2O3 ceramic lasing medium using a three-mirror folded laser cavity.We measured a slope efficiency of 73%,which allowed us to retrieve the cross-relaxation coefficient.The behavior of our system was modeled via a set of macroscopic rate equations in both the quasi continuous wave and the pulsed pumping regime.Numerical solutions were obtained,showing a good agreement with the experimental findings.The numerical solution also yielded a cross-relaxation coefficient in very good agreement with the measured one,showing that the cross-relaxation phenomenon approaches the maximum theoretical efficiency.展开更多
In order to obtain the robust high-resolution beamforming, a high order cross sensor processing(CSP) approach is developed. According to the relation ship between the target bearing and the phase difference of each el...In order to obtain the robust high-resolution beamforming, a high order cross sensor processing(CSP) approach is developed. According to the relation ship between the target bearing and the phase difference of each element receiving signal, this method exploits the property that the same diagonal of covariance matrix with the same phase difference and obtains(2M-1)(N-1)virtual elements(N is the original array number) by executing M order CSP. The extended virtual elements can effectively increase the physical aperture of linear array, reduce the main lobe width of beam-forming, and improve the bearing resolution. The CSP method accumulates the data on the same sub-diagonal of the covariance matrix, which can decrease the impact of background noise on beam-forming. The theoretical analysis and experimental results both show that this method has high resolution in bearing estimation, compared with the MUSIC method, which has better robustness under the lower signal-to-noise ratio(SNR).展开更多
基金EU Horizon 2020 Research and Innovation Program EuPRAXIA Preparatory Phase,under Grant Agreement No.101079773,EU Horizon IFAST,under Grant Agreement No.101004730This research has been co-funded by the European Union-NextGeneration EU‘Integrated infrastructure initiative in Photonic and Quantum Sciences’-I-PHOQS(IR0000016,ID D2B8D520,CUP B53C22001750006)+1 种基金‘EuPRAXIA Advanced Photon Sources’-EuAPS(IR0000030,CUP I93C21000160006)the Project‘Tuscany Health Ecosystem-THE’‘Spoke 1-Advanced Radiotherapies and Diagnostics in Oncology’funded by the NextGenerationEU(PNRR),Codice progetto ECS00000017,D.D.MUR No.105523 May 2022.
文摘We report the characterization of the pump absorption and emission dynamic properties of a Tm:Lu2O3 ceramic lasing medium using a three-mirror folded laser cavity.We measured a slope efficiency of 73%,which allowed us to retrieve the cross-relaxation coefficient.The behavior of our system was modeled via a set of macroscopic rate equations in both the quasi continuous wave and the pulsed pumping regime.Numerical solutions were obtained,showing a good agreement with the experimental findings.The numerical solution also yielded a cross-relaxation coefficient in very good agreement with the measured one,showing that the cross-relaxation phenomenon approaches the maximum theoretical efficiency.
基金supported by the National Natural Science Foundation of China(61372180)the Young Talent Frontier Project of Institute of Acoustics of Chinese Academy of Sciences(Y454341261)
文摘In order to obtain the robust high-resolution beamforming, a high order cross sensor processing(CSP) approach is developed. According to the relation ship between the target bearing and the phase difference of each element receiving signal, this method exploits the property that the same diagonal of covariance matrix with the same phase difference and obtains(2M-1)(N-1)virtual elements(N is the original array number) by executing M order CSP. The extended virtual elements can effectively increase the physical aperture of linear array, reduce the main lobe width of beam-forming, and improve the bearing resolution. The CSP method accumulates the data on the same sub-diagonal of the covariance matrix, which can decrease the impact of background noise on beam-forming. The theoretical analysis and experimental results both show that this method has high resolution in bearing estimation, compared with the MUSIC method, which has better robustness under the lower signal-to-noise ratio(SNR).
