High signal-to-noise ratio can be achieved with the electron multiplying charge-coupled-device（EMCCD） applied in the Shack–Hartmann wavefront sensor（S–H WFS） in adaptive optics（AO）.However,when the brightness ...High signal-to-noise ratio can be achieved with the electron multiplying charge-coupled-device（EMCCD） applied in the Shack–Hartmann wavefront sensor（S–H WFS） in adaptive optics（AO）.However,when the brightness of the target changes in a large scale,the fixed electron multiplying（EM） gain will not be suited to the sensing limitation.Therefore an auto-gain-control method based on the brightness of light-spots array in S–H WFS is proposed in this paper.The control value is the average of the maximum signals of every light spot in an array,which has been demonstrated to be kept stable even under the influence of some noise and turbulence,and sensitive enough to the change of target brightness.A goal value is needed in the control process and it is predetermined based on the characters of EMCCD.Simulations and experiments have demonstrated that this auto-gain-control method is valid and robust,the sensing SNR reaches the maximum for the corresponding signal level,and especially is greatly improved for those dim targets from 6 to 4 magnitude in the visual band.展开更多
A multi-channel synchronous demodulation system of a polarized low-coherence interferometer(PLCI)based on a matrix charge-coupled-device(CCD)is proposed and demonstrated.By using special designs,the system allows the ...A multi-channel synchronous demodulation system of a polarized low-coherence interferometer(PLCI)based on a matrix charge-coupled-device(CCD)is proposed and demonstrated.By using special designs,the system allows the signals from different channels to be received and demodulated synchronously.Multichannel air pressure experiments were implemented to verify the effectiveness of the proposed system.The experiment results showed that the Fabry–Perot(F–P)sensors could be demodulated synchronously with a high tolerance for light sources and sensors,which indicated that any sensor and light source that can be demodulated by PLCI were allowed to be employed,leading to a wide application in the field of multichannel synchronous measurement.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11174274,61205021,and 61405194)the State Key Laboratory of Applied Optics,Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences
文摘High signal-to-noise ratio can be achieved with the electron multiplying charge-coupled-device（EMCCD） applied in the Shack–Hartmann wavefront sensor（S–H WFS） in adaptive optics（AO）.However,when the brightness of the target changes in a large scale,the fixed electron multiplying（EM） gain will not be suited to the sensing limitation.Therefore an auto-gain-control method based on the brightness of light-spots array in S–H WFS is proposed in this paper.The control value is the average of the maximum signals of every light spot in an array,which has been demonstrated to be kept stable even under the influence of some noise and turbulence,and sensitive enough to the change of target brightness.A goal value is needed in the control process and it is predetermined based on the characters of EMCCD.Simulations and experiments have demonstrated that this auto-gain-control method is valid and robust,the sensing SNR reaches the maximum for the corresponding signal level,and especially is greatly improved for those dim targets from 6 to 4 magnitude in the visual band.
基金supported by the National Natural Science Foundation of China(Nos.61735011,61675152 and 61505139)National Instrumentation Program of China(No.2013YQ030915)China Postdoctoral Science Foundation(No.2016M590200)
文摘A multi-channel synchronous demodulation system of a polarized low-coherence interferometer(PLCI)based on a matrix charge-coupled-device(CCD)is proposed and demonstrated.By using special designs,the system allows the signals from different channels to be received and demodulated synchronously.Multichannel air pressure experiments were implemented to verify the effectiveness of the proposed system.The experiment results showed that the Fabry–Perot(F–P)sensors could be demodulated synchronously with a high tolerance for light sources and sensors,which indicated that any sensor and light source that can be demodulated by PLCI were allowed to be employed,leading to a wide application in the field of multichannel synchronous measurement.
