A Bose–Einstein condensate with a large atom number is an important experimental platform for quantum simulation and quantum information research.An optical dipole trap is the a conventional way to hold the ultracold...A Bose–Einstein condensate with a large atom number is an important experimental platform for quantum simulation and quantum information research.An optical dipole trap is the a conventional way to hold the ultracold atoms,where an atomic cloud is evaporatively cooled down before reaching the Bose–Einstein condensate.A carefully designed trap depth controlling curve is typically required to realize the optimal evaporation cooling.We present and demonstrate a simple way to optimize the evaporation cooling in a crossed optical dipole trap.A polyline shape optical power control profile is easily obtained with our method,by which a pure Bose–Einstein condensate with atom number 1.73×10^5 is produced.Theoretically,we numerically simulate the optimal evaporation cooling using the parameters of our apparatus based on a kinetic theory.Compared to the simulation results,our evaporation cooling shows a good performance.We believe that our simple method can be used to quickly realize evaporation cooling in optical dipole traps.展开更多
We report the generation of heralded single photons with Gaussian-shape temporal waveforms through the spatial light modulation technique in an atomic ensemble. Both the full width at half maximum and the peak positio...We report the generation of heralded single photons with Gaussian-shape temporal waveforms through the spatial light modulation technique in an atomic ensemble. Both the full width at half maximum and the peak position of the Gaussian waveform can be controlled while the single photon nature holds well. We also analyze the bandwidth of the generated single photons in frequency domain and show how the sidebands of the frequency spectrum are modified by the shape of the temporal waveform. The generated single photons are especially suited for the realization of high efficiency quantum storage based on electromagnetically induced transparency.展开更多
We demonstrate a long-coherent-time coupling between microwave and optical fields through cold atomic ensembles.The phase information of the microwave field is stored in a coherent superposition state of a cold atomic...We demonstrate a long-coherent-time coupling between microwave and optical fields through cold atomic ensembles.The phase information of the microwave field is stored in a coherent superposition state of a cold atomic ensemble and is then read out by two optical fields after 12 ms.A similar operation of mapping the phase of optical fields into a cold atomic ensemble and then retrieving by microwave is also demonstrated.These studies demonstrate that long-coherent-time cold atomic ensembles could resonantly couple with microwave and optical fields simultaneously,which paves the way for realizing high-efficiency,high-bandwidth,and noiseless atomic q uant um converters.展开更多
基金Supported by the National Key Research and Development Program of China(Grant Nos.2016YFA0301803 and 2016YFA0302800)the Key-Area Research and Development Program of Guang Dong Province(Grant No.2019B030330001)+2 种基金the National Natural Science Foundation of China(Grant Nos.61378012,91636218,11822403,11804104,11804105,61875060 and U1801661)the Natural Science Foundation of Guangdong Province(Grant Nos.2018A030313342 and 2018A0303130066)the Key Project of Science and Technology of Guangzhou(Grant No.201804020055)。
文摘A Bose–Einstein condensate with a large atom number is an important experimental platform for quantum simulation and quantum information research.An optical dipole trap is the a conventional way to hold the ultracold atoms,where an atomic cloud is evaporatively cooled down before reaching the Bose–Einstein condensate.A carefully designed trap depth controlling curve is typically required to realize the optimal evaporation cooling.We present and demonstrate a simple way to optimize the evaporation cooling in a crossed optical dipole trap.A polyline shape optical power control profile is easily obtained with our method,by which a pure Bose–Einstein condensate with atom number 1.73×10^5 is produced.Theoretically,we numerically simulate the optimal evaporation cooling using the parameters of our apparatus based on a kinetic theory.Compared to the simulation results,our evaporation cooling shows a good performance.We believe that our simple method can be used to quickly realize evaporation cooling in optical dipole traps.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0301800 and 2016YFA0302800the National Natural Science Foundation of China under Grant Nos 11822403,91636218,U1801661,11704131,11804105 and 11804104+1 种基金the Natural Science Foundation of Guangdong Province under Grant Nos 2015TQ01X715 and 2018A0303130066the KPST of Guangzhou under Grant No 201804020055.
文摘We report the generation of heralded single photons with Gaussian-shape temporal waveforms through the spatial light modulation technique in an atomic ensemble. Both the full width at half maximum and the peak position of the Gaussian waveform can be controlled while the single photon nature holds well. We also analyze the bandwidth of the generated single photons in frequency domain and show how the sidebands of the frequency spectrum are modified by the shape of the temporal waveform. The generated single photons are especially suited for the realization of high efficiency quantum storage based on electromagnetically induced transparency.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0301800 and 2016YFA0302800the National Natural Science Foundation of China under Grant Nos 11822403,91636218,U1801661,11704131 and 61875060+2 种基金the Natural Science Foundation of Guangdong Province under Grant Nos 2016A030310462 and 2015TQ01X715the KPST of Guangzhou under Grant No 201804020055the SRFGS of SCNU.
文摘We demonstrate a long-coherent-time coupling between microwave and optical fields through cold atomic ensembles.The phase information of the microwave field is stored in a coherent superposition state of a cold atomic ensemble and is then read out by two optical fields after 12 ms.A similar operation of mapping the phase of optical fields into a cold atomic ensemble and then retrieving by microwave is also demonstrated.These studies demonstrate that long-coherent-time cold atomic ensembles could resonantly couple with microwave and optical fields simultaneously,which paves the way for realizing high-efficiency,high-bandwidth,and noiseless atomic q uant um converters.