外场参数对超冷原子向异核三原子分子转化的影响

摘要

We investigate the effects of external field parameters,including the strength of Rabi pulse,its width,and single-photon detuning,on conversion from ultracold atoms to heteronuclear triatomic molecules by two-photon stimulated Raman adiabatic passage.It is found that the conversion efficiency of the system decreases first with the strength of the Stokes pulse increasing,then oscillates,and finally approaches a stable value,which is less than 1.But for the pump pulse,the efficiency first increases with the increase of the pulse intensity,and then approaches 1 quickly.The results show that the two pulses play different roles in the conversion.The pulse width can not only determine the final conversion efficiency,but also be used to reflect the time needed for stable conversion.The system has a higher efficiency of conversion for red detuning pump laser,but the blue detuning is not conducive to the formation of the molecules.In addition,the differences of the adiabaticity and conversion efficiency among different reaction pathways are discussed.%文章研究了利用双光子受激拉曼绝热暗通道技术实现超冷原子向异核三原子分子转化过程中,可控外场参量（包括拉比脉冲的强度,脉宽以及单光子失谐等）对系统绝热性和转化效率的影响.结果发现,系统的转化效率随斯托克斯光强度的增大先减小,后振荡,最终趋于小于1的稳定值,而随抽运光强的增大先增大,然后很快趋于1,表明抽运光和斯托克斯光对超冷分子的形成具有不同的作用.脉冲宽度既能决定最终转化效率的大小,也能反映达到稳定转化所需的时间.单光子失谐为红失谐时,系统有比较高的稳定转化效率,而蓝失谐光脉冲则不利于超冷分子的形成.另外,还讨论了超冷异核三原子分子转化系统在经历不同反应通道时绝热性和转化效率的差别.