Doppler cooling of^(88)Sr atoms is studied in the presence of off-resonant red-detuned fluctuating laser fields.Using a semi-classical approach,we show that the relevant physical quantities in the cooling process,such...Doppler cooling of^(88)Sr atoms is studied in the presence of off-resonant red-detuned fluctuating laser fields.Using a semi-classical approach,we show that the relevant physical quantities in the cooling process,such as optical forces,the damping coefficient,Doppler temperature,and atom number in the trap,are strongly affected by the laser amplitude and phase fluctuations.We find that the Doppler cooling limit is higher than the predicted Doppler theory for non-fluctuating lasers.This implies an additional heating mechanism exists due to the laser fluctuations.Furthermore,our numerical analysis shows that the effect of laser power stability on reducing the number of trapped atoms in a magneto-optical trap is more substantial than the effect of laser linewidth.展开更多
A new approach based on microcantilevers is presented to detect infrared photons with high sensitivity. Infrared photons are measured by monitoring the amplitude change of a vibrating microcantilever under light press...A new approach based on microcantilevers is presented to detect infrared photons with high sensitivity. Infrared photons are measured by monitoring the amplitude change of a vibrating microcantilever under light pressure force.The irradiating light is modulated into sinusoidal and pulsed waves,and to be in-phase and anti-phase with the cantilever driving signal.A linear relationship between the amplitude change of the cantilever and the light power distributing on the cantilever was observed.Under a vacuum of 10^（-4） Pa,an infrared light power of 7.4 nW was detected with the cantilever.The in-phase and anti-phase modulation to the cantilever vibration using a pulsed light results in an enhanced response of the cantilever.展开更多
文摘Doppler cooling of^(88)Sr atoms is studied in the presence of off-resonant red-detuned fluctuating laser fields.Using a semi-classical approach,we show that the relevant physical quantities in the cooling process,such as optical forces,the damping coefficient,Doppler temperature,and atom number in the trap,are strongly affected by the laser amplitude and phase fluctuations.We find that the Doppler cooling limit is higher than the predicted Doppler theory for non-fluctuating lasers.This implies an additional heating mechanism exists due to the laser fluctuations.Furthermore,our numerical analysis shows that the effect of laser power stability on reducing the number of trapped atoms in a magneto-optical trap is more substantial than the effect of laser linewidth.
基金Project supported by the Ministry of Science and Technology of China(Nos.2009CB320305,2011CB933102)
文摘A new approach based on microcantilevers is presented to detect infrared photons with high sensitivity. Infrared photons are measured by monitoring the amplitude change of a vibrating microcantilever under light pressure force.The irradiating light is modulated into sinusoidal and pulsed waves,and to be in-phase and anti-phase with the cantilever driving signal.A linear relationship between the amplitude change of the cantilever and the light power distributing on the cantilever was observed.Under a vacuum of 10^（-4） Pa,an infrared light power of 7.4 nW was detected with the cantilever.The in-phase and anti-phase modulation to the cantilever vibration using a pulsed light results in an enhanced response of the cantilever.
