Electromagnetically Induced Transparency Precision Spectroscopy Of Rubidium Atoms And Its Application In Laser Frequency Stabilization

The study of the light-matter interaction is a significant part of atomic and molecular physics.An outstanding example is electromagnetically induced transparency(EIT),in which the propagation of the weak probe laser beam in optical media is controlled by the strong coupling laser beam.EIT is a kind of nonlinear optical effect of the light-matter interaction,making the medium with high transmissivity and deeply changing its dispersion.EIT has attracted much attention with a wide range of applications,such as slow light,laser frequency stabilization,laser without inversion,atomic magnetometer,precision measurement and so on.In magnetic fields,atomic levels usually split for Zeeman effect and the EIT technology supplies a precision method to study the Zeeman effect of atoms.In addition,the Rydberg atom has special application value in electric field measurement,owing to its large transition electric dipole moment.The Rydberg-EIT has been developed into a feasible high-precision RF field measurement technology.In this dissertation,by irradiating the atoms to highly excited Rydberg state through a two-photon resonance ladder-type EIT,we study the nonlinear optical properties of Rubidium atoms and measure the high-resolution splitting spectra in two different conditions of applying external magnetic field and microwave electric field.The main research works enclosed in this thesis include:(1)The A-type EIT spectra of the D2 line of rubidium atoms in zero field and external magnetic field are investigated and the high-resolution EIT spectrum of rubidium atoms is adopted to achieve frequency tunable offset locking of the laser.Firstly,we exprimentally obtain the ?-type EIT spectrum of zero magnetic field in the multi-level system configured by the ground state(5S1/2)and low excited state(5P3/2)of the D2 line.Besides,to study the behavior of EIT spectrum under magnetic field,the corresponding EIT spectrum splittings are measured at magnetic field is aligned parallel and orthogonal to the direction of light propagation,separately.Based on the EIT dispersion theory,we build up a simulation model considering all interactions in the Hamiltonian of atom in magnetic field.The simulation explains the experimental observations very well.Finally,the laser frequency tunable offset locking system is realized by using the high resolution EIT Zeeman splitting spectrum of the rubidium atom in the external magnetic field.The laser frequency has high stability after locking.And the laser frequency locking position can be changed by adjusting the external applied magnetic field.(2)The EIT spectrum without magnetic field in ladder-type system through transition 5S1/2-5P3/2-nD of Rubidium atoms is investigated,as well as its corresponding EIT polarization spectroscopy in external magnetic field.Moreover,a modulation-free artificial PDH laser frequency stabilization technique is realized based on the linear combination of the polarization spectroscopy of EIT in zero field and magnetic field.The Rubidium atoms in ground state are excited to high excited Rydberg states via the double-resonant optical pumping effects(DROP)of 780 nm laser and 480 nm laser,i.e.,5S1/25P3/248D5/2.The Rydberg-EIT spectrum with MHz resolution is obtained.The EIT resonance spectra of the 48D5/2 states of 85Rb atom are studied under different probe laser intensities and cell temperature.We then experimentally measure the EIT polarization spectroscopy of 48D5/2 states at different cell temperatures and magnetic fields.Finally,the linear combination of polarization spectroscopy of EIT of zero field and magnetic field is used to construct an artificial modulation-free PDH error locking signal,then to lock the laser frequency.The corresponding artificial PDH laser frequency stabilization system has good frequency stability against disturbance from environmental noise.(3)The EIT spectrum via ladder-type transition 5S1/2-5P3/2-nS of Rubidium atoms in zero-field and microwave electric field is measured.When no microwave electric field applied,the 50S1/2 EIT spectrum of 85Rb atom is measured,and then the corresponding EIT-AT splitting spectra under different microwave electric field intensities are studied.The EIT-AT splitting spectrum is due to the Aulter-Towns effect caused by the interaction between Rydberg state and microwave electric field.And the splitting interval between the two peaks of EIT-AT spectrum is proportional to the applied electric field intensity.Finally,the 85Rb Rydberg-EIT system is used as an atomic antenna to realize the detection of radio electrical signals in space and signal transmission.