The negatively charged nitrogen vacancy(NV^(−))center ensemble in as-grown chemical vapor deposition(CVD)diamond is a promising candidate for quantum sensing due to its long coherence time and excellent optical proper...The negatively charged nitrogen vacancy(NV^(−))center ensemble in as-grown chemical vapor deposition(CVD)diamond is a promising candidate for quantum sensing due to its long coherence time and excellent optical properties.However,achieving a high concentration of NV^(−)centers in as-grown CVD diamond remains a critical challenge,which constrains the performance of NV^(−)based sensors.In this study,we observe that NV^(−)center formation efficiency is significantly enhanced during the initial growth phase,with a coherence time T_(2)^(*)of 1.1μs.These findings demonstrate that high-concentration NV^(−)centers can be achieved in as-grown diamonds,greatly enhancing their utility in high-performance magnetometers and quantum sensing.展开更多
The back-propagation(BP)neural network is proposed to correct nonlinearity and optimize the force measurement and calibration of an optical tweezer sys-tem.Considering the low convergence rate of the BP algo-rithm,the...The back-propagation(BP)neural network is proposed to correct nonlinearity and optimize the force measurement and calibration of an optical tweezer sys-tem.Considering the low convergence rate of the BP algo-rithm,the Levenberg-Marquardt(LM)algorithm is used to improve the BP network.The proposed method is experimentally studied for force calibration in a typical optical tweezer system using hydromechanics.The result shows that with the nonlinear correction using BP net-works,the range of force measurement of an optical tweezer system is enlarged by 30%and the precision is also improved compared with the polynomial fitting method.It is demonstrated that nonlinear correction by the neural network method effectively improves the per-formance of optical tweezers without adding or changing the measuring system.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11374280 and 50772110).
文摘The negatively charged nitrogen vacancy(NV^(−))center ensemble in as-grown chemical vapor deposition(CVD)diamond is a promising candidate for quantum sensing due to its long coherence time and excellent optical properties.However,achieving a high concentration of NV^(−)centers in as-grown CVD diamond remains a critical challenge,which constrains the performance of NV^(−)based sensors.In this study,we observe that NV^(−)center formation efficiency is significantly enhanced during the initial growth phase,with a coherence time T_(2)^(*)of 1.1μs.These findings demonstrate that high-concentration NV^(−)centers can be achieved in as-grown diamonds,greatly enhancing their utility in high-performance magnetometers and quantum sensing.
基金supported by the National Natural Science Foundation of China(Grant No.10474094).
文摘The back-propagation(BP)neural network is proposed to correct nonlinearity and optimize the force measurement and calibration of an optical tweezer sys-tem.Considering the low convergence rate of the BP algo-rithm,the Levenberg-Marquardt(LM)algorithm is used to improve the BP network.The proposed method is experimentally studied for force calibration in a typical optical tweezer system using hydromechanics.The result shows that with the nonlinear correction using BP net-works,the range of force measurement of an optical tweezer system is enlarged by 30%and the precision is also improved compared with the polynomial fitting method.It is demonstrated that nonlinear correction by the neural network method effectively improves the per-formance of optical tweezers without adding or changing the measuring system.
