We report the generation of a crossed,focused,optical vortex beam by using a pair of hybrid holograms,which combine the vortex phase and lens phase onto a spatial light modulator.We study the intensity distributions o...We report the generation of a crossed,focused,optical vortex beam by using a pair of hybrid holograms,which combine the vortex phase and lens phase onto a spatial light modulator.We study the intensity distributions of the vortex beam in free propagation space,and the relationship of its dark spot size with the incident Gaussian beam’s waist,the lens’s focal length,and its orbital angular momentum.Our results show that the crossed,focused,vortex beam’s dark spot size can be as small as 16.3μm and adjustable by the quantum number of the orbital angular momentum,and can be used to increase the density of trapped molecules.Furthermore,we calculate the optical potential of the blue-detuned,crossed vortex beam for MgF molecules.It is applicable to cool and trap neutral molecules by intensity-gradient-induced Sisyphus cooling,as the intensity gradient of such vortex beam is extremely high near the focal point.展开更多
Here we propose a scheme to slow MgF molecules by using EOM-based frequency-chirped radiation pressure slowing.The scheme well addresses the need for a rapid chirp rate while light molecules are being laser slowed,who...Here we propose a scheme to slow MgF molecules by using EOM-based frequency-chirped radiation pressure slowing.The scheme well addresses the need for a rapid chirp rate while light molecules are being laser slowed,whose scattering rate and recoil velocity are large.Two EOMs are used to compensate the rapidly changing Doppler shifts arised from the movement of molecules,and to cover the hyperfine energy structure of MgF,respectively.Based the scattering rate maps calculated from an optical Bloch equation model,individual molecule trajectories are simulated by using a semi-classical three-dimensional Monte Carlo approach.We show how the modulation configuration of EOM and the magnetic field influence the slowing results.The study shows that a cryogenic buffer gas-cooled MgF beam source is possible to be slowed down with a number of∼1.4×10^(6)–10^(7),and the final forward speed peaks at∼10 m/s near the capture velocity of a molecular MOT.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11834003 and 91836103).
文摘We report the generation of a crossed,focused,optical vortex beam by using a pair of hybrid holograms,which combine the vortex phase and lens phase onto a spatial light modulator.We study the intensity distributions of the vortex beam in free propagation space,and the relationship of its dark spot size with the incident Gaussian beam’s waist,the lens’s focal length,and its orbital angular momentum.Our results show that the crossed,focused,vortex beam’s dark spot size can be as small as 16.3μm and adjustable by the quantum number of the orbital angular momentum,and can be used to increase the density of trapped molecules.Furthermore,we calculate the optical potential of the blue-detuned,crossed vortex beam for MgF molecules.It is applicable to cool and trap neutral molecules by intensity-gradient-induced Sisyphus cooling,as the intensity gradient of such vortex beam is extremely high near the focal point.
基金supports are from the National Natural Science Foundation of China under Grant Nos.11834003,91836103,and 91536218.
文摘Here we propose a scheme to slow MgF molecules by using EOM-based frequency-chirped radiation pressure slowing.The scheme well addresses the need for a rapid chirp rate while light molecules are being laser slowed,whose scattering rate and recoil velocity are large.Two EOMs are used to compensate the rapidly changing Doppler shifts arised from the movement of molecules,and to cover the hyperfine energy structure of MgF,respectively.Based the scattering rate maps calculated from an optical Bloch equation model,individual molecule trajectories are simulated by using a semi-classical three-dimensional Monte Carlo approach.We show how the modulation configuration of EOM and the magnetic field influence the slowing results.The study shows that a cryogenic buffer gas-cooled MgF beam source is possible to be slowed down with a number of∼1.4×10^(6)–10^(7),and the final forward speed peaks at∼10 m/s near the capture velocity of a molecular MOT.
