Measurement Of Hyperfine Structure Of Cesium Excited State And The Spectral Application Research Based On The Elemental Lamp

The measurement of atomic hyperfine structure has always been a subject of great concern,and it is important for both basic research and practical applications.Fine structure of atom arises from the interaction of the spin and orbital motions of electrons.The atomic hyperfine splitting structure is caused by the nuclear spin effects inside the atoms,which is characterized by the magnetic dipole A_hfsand electric quadrupole B_hfshyperfine constants.Some theoretical calculation methods of hyperfine structure including the multi-configuration Dirac-Fock method,many-body perturbation theory,etc.,are sensitive to electron correlation effects,relaxation effects,relativistic effects and shielding effects of the inner electrons in atoms.The theoretical calculation models are very complex,and the difference between calculation results of different models sometimes is significant,so it is needed to develop a precise method of measuring the hyperfine structure of atoms.In this paper,we developed a method for self-measurement of the hyperfine structure of atomic excited states,and demonstrated a Faraday anomalous dispersion optical filter using a hollow cathode lamp（HCL）.Using a hollow cathode lamp to explore the atomic spectroscopy and related application research,may greatly simplify the similar experimental device,especially for high melting point of metal atoms,to carry out related research has important research significance.Specific work of the paper are as follows:（1）Experimental demonstration of self-measurements of hyperfine structures of atomic excited states.Based on the ¹³³Cs 6S_1/2-6P_3/2-6D_5/2（852 nm+917 nm）system,the hyperfine structure constant of excited 6D_5/2was measured using optical double resonance spectroscopy（OODR）and saturation absorption spectroscopy（SAS）without any additional frequency calibration tools.Experimentally,the frequency of pump laser at 852 nm is scanned over the 6S_1/2-6P_3/2transition,and the probe laser at 917 nm keeps nearly resonant on the 6P_3/2-6D_5/2transition,we can obtain the SAS from the lower transition and the OODR spectrum from the upper transition.Using SAS as a frequency ruler to calibrate the frequency axis of OODR spectrum,we measured the hyperfine frequency intervals of6D_5/2excited state.Finally,according to the measured hyperfine frequency interval values,the magnetic dipole-hyperfine coupling constant of 6D_5/2state is derivedA_hfs=-4.60（5）MHz and the electric quadrupole hyperfine coupling constant isB_hfs=0.23（47）MHz,A_hfsare agreeing with the results reported in previous literature,and B_hfshave little influence on atomic hyperfine structure,resulting in large errors calculated by different measurement methods,B_hfsis less consistent with the results in previous literature.（2）Experimental study on the realization of Faraday anomalous dispersion optical filter based on a hollow cathode lamp.Based on the ¹³³Cs 6S_1/2-6P_3/2transition,a Faraday anomalous dispersion optical filter at 852 nm is realized in a commercial-type hollow cathode lamp.In the experiment,we control the number density of cesium atoms in HCL by adjusting its working current.When the working current of the cesium HCL is 1-4 m A,the FADOF signal is single-peak resonant signal;when the working current is 6-10 m A,the signal is linear wing.At the optimizing experimental parameters,the transmittance of the optical filter can reach up to 77%.The above results are valuable in frequency stabilization laser and free space optical communication systems.