Investigation Of Coherent Spectroscopy Of Excited States Of Cesium Atoms

Laser spectroscopy is a spectroscopic technique using a laser as a light source.Since the laser has good monochromaticity,good directivity,high brightness,and strong coherence,it greatly improves the resolution of spectral lines and the sensitivity of detection.In the course of spectrum development,saturated absorption spectrum,fluorescence spectrum,modulation transfer spectrum,and polarization spectrum have been widely used in laser stabilization,laser cooling/capturing neutral atoms,Bose-Einstein condensation,and cold atomic clocks.These spectroscopic techniques are mainly focused on experiments in the ground state-excited state.Spectral studies between intermediate excited states and higher excited states also have important implications in theoretical research and practical applications such as providing experimental tests for theoretical studies of atomic energy level structures,laser frequency stabilization in fiber-optic communication bands,and two-color laser cooling and trapping of neutrality atomic,atomic filters,four-wave mixing,and frequency upconversion nonlinear optics.Focused on the cesium?Cs?6S_1/2-6P_3/2-7S_1/2/2 and 8S_1/2?852.3nm+1469.9nmand852.3nm+794.6nm?ladder-typeatomicsystem,this dissertation investigated the atomic excited state spectra and quantum coherence effect which are used for the measurement of the hyperfine structure constants of the atom excited state and laser frequency stabilization.The main work is described in the following aspects:1)Most atomic excited-state spectroscopy techniques require that the atoms in the ground state are brought to the excited state.For this reason,firstly,the saturation absorption spectra of the two sets of spectral curves with the same shape as the 6S_1/2?F=3?-6P_3/2/2 and 6S_1/2?F=4?-6P_3/2/2 ground states were obtained.A simple way to distinguish the two spectral lines?no longer rely on the measurement of the wavelength meter?are proposed,which is used to lock the frequency of the 852.3 nm diode laser to a pair of 6S_1/2-6P_3/2hyperfine transition lines.The atomic population of hyperfine energy levels in the intermediate excited state 6P_3/2/2 is achieved,which lays an experimental foundation for the subsequent acquisition of various excited state spectroscopy and coherence effects.2)Based on the cesium?Cs?6S_1/2-6P_3/2-7S_1/2?852.3nm+1469.9nm?ladder-type atomic system,using Optical optical double resonance spectroscopy?OODR?and electro-optic modulator?EOM?sideband technology,we propose a method for accurately measuring the energy level structure of atomic excited states and associated physical constants for the measurement of the magnetic dipole hyperfine constant in the 7S_1/2/2 state of cesium atoms.The result is A_hfs=?545.93±0.06?MHz,which is consistent with previously reported experimental results.3)Based on the cesium?Cs?6S_1/2-6P_3/2-8S_1/2?852.3nm+794.6nm?ladder-type atomic system,double resonance optical pumping?DROP?was obtained in the experiment,and The effect of 852.3nm and 794.6nm laser beam on DROP under different polarization combinations and in the co/counter-propagate configuration were simply studied.When the 852.3nm and 794.6nm laser beams are counter-propagating in cesium atom media,the linewidth of DROP is narrower than the linewidth of DROP?co-propagating?due to the existence of quantum coherence effect.4)Based on the cesium?Cs?6S_1/2-6P_3/2-8S_1/2?852.3nm+794.6nm?ladder-type atomic system,we investigated a detailed study of excited two-color polarization spectroscopy?TCPS?:Experiments have measured the effects of various experimental parameters such as laser polarization,frequency detuning,intensity,and the co/counter-propagate experimental configuration on TCPS;The experimental results show that,as in the DROP spectrum,due to the quantum coherence effect in the ladder-type energy level system,the linewidth of the TCPS in the counter-propagate is narrower;And developed TCPS with different detection methods?frequency-locked852.3nm laser as probe light?to improve the signal-to-noise ratio of the TCPS.Finally,the TCPS is used for the frequency locking of a 794.6nm diode laser,which effectively improves the frequency stability of laser.