The Spectroscopy Of Rydberg Electromagnetically Induced Transparency In External Magnetic Field

Rydberg atoms are highly excited atoms with large principal quantum number n>>1,possessing extraordinary properties,such as large orbital radius??n²?,long lifetime??n³?,strong dipole-dipole interaction??n²?and large polarizabilities??n⁷?,so Rydberg atoms have raised widely attention.According to the strong dipole-dipole interaction,people have realized the manipulation of quantum gates based on blocked effects,and these offer considerable potential for applications in quantum information processing.In Rydberg atoms,the valence electrons have binding energies that decrease as n^-2,so these atoms are very sensitive to external field?electric fields,magnetic fields and microwave fields?.A new quantum interference effect,cascade Rydberg EIT,is extensively investigated theoretically and experimentally.We can understand the interaction between atoms and external fields by studying the influence of external fields on Rydberg EIT spectroscopy,and it can also be used as an antenna-free,all-optical,and more sensitive technique to measure weak electromagnetic and microwave fields.The Rydberg EIT are performed in a ¹³³Cs vapor cell,6P_3/2 and nS_1/2/D_3/2,5/2 states are strongly coupled and transmissions are detected via probe laser resonated in a 6S_1/2?6P_3/2 transition.The uniform magnetic field in the axis of the vapor cell is produced by a cylindrical solenoid.We observed the dependence of Rydberg EIT spectroscopy in magnetic field on power and polarizability of probe and coupling laser fields,strength of magnetic field,temperature of ¹³³Cs vapor,principal and angular quantum numbers of Rydebrg state.We use the master equation and quantum Monte Carlo wave function approach to quantitatively model the experimental results.Details are as following:1.Solve the master equation of density matrix of Rydberg atom in the semiclassical model describing the interactions between lasers and cascade three-level system,and simulate the Rydberg EIT spectra.Calculate the magnetic interactions of three levels and analysis the influence of relative transition dipole moment on Rydberg EIT.We use a quantum Monte Carlo wave-function approach to quantitatively model the spectra and their asymmetry behavior.We use the quantum Monte Carlo wave-function approach to obtain the probe-photon scattering rate per atom,considering both the magnetic and hyperfine interaction.Simulated spectra are in good agreement with the experimental data.2.We investigate the influence of Rydberg EIT spectra on Zeeman sublevels through tuning the strength of magnetic field,principal and angular quantum number of Rydberg states.The dependence of Rydberg EIT spectra on polarizability of laser fields is demonstrated experimentally.3.We observed the nonlinear and asymmetrical splitting of Rydberg EIT spectra in magnetic field,and the quadratic Zeeman effect of 6P_3/2 state and imperfect optical pumping are main reasons.We also simulated the optical pumping effect on a grid of atom velocities v in the cell and over a range of coupling-laser detuning ?C,and analysis the interplay between optical pumping and EIT.The electron-spin splitting spectroscopy of Rydberg atoms are observed in experiment,due to the Paschen-Back magnetic interaction of Rydberg atoms.The innovations of this work:1.We perform the Rydberg EIT spectra in a room-temperature ¹³³Cs vapor cell,in magnetic fields up to 100 Gauss,and investigate the influence of Rydberg EIT spectra on Zeeman sublevels through tuning the strength of magnetic field,principal and angular quantum number of Rydberg states.The dependence of Rydberg-EIT on the polarizations of probe and coupling laser fields is studied,and shown mainly due to the strengths of relative dipole matrix elements between Zeeman sublevels.2.We introduce a quantum Monte Carlo wave-function approach to quantitatively model the experimental results.It has been shown that the quantum Monte Carlo wave-function method is equivalent to the standard density matrix analysis,but is more advantages in dealing with the large system.We demonstrated the nonlinear and asymmetrical splitting of Rydberg EIT spectra in magnetic field,and explained the quadratic Zeeman effect of 6P_3/2 state and imperfect optical pumping are main reasons.We also analyzed the interplay between optical pumping and EIT.The electron-spin splitting spectroscopy of Rydberg atoms are observed in experiment,corresponding to the Paschen-Back magnetic interaction of Rydberg atoms.3.We demonstrate a robust method of direct coupling laser frequency locking on the Zeeman sublevel transitions,with continuously tunable frequency range from-35 MHz to +35 MHz,which is based on Rydberg EIT spectra in magnetic field.Compensate for the frequency shift of ±50?±350 MHz usually offered by a commercial acoustic-optical modulator.