Measurement Of Fine Structure Spectrum Of 47D States In Cesium Atoms

The Rydberg atom has become a research hotspot because of its long life,large polarizability,low binding energy,and strong long-range interactions.The three-level ladder-type EIT of Rydberg atoms not only has the properties of ordinary EIT but also carries the properties of the Rydberg atom itself,which makes the EIT of the Rydberg atom has predictable application prospects in microwave electric field sensing,quantum computer,single photon source,and quantum entanglement.The Rydberg EIT provides a completely new,non-destructive method for studying the properties of the Rydberg atoms and also provides a method for measuring interactions between Rydberg atoms.Trap loss spectroscopy is a conventional method in the field of ultra-cold molecular spectroscopy.Especially in the process of generating ultracold molecules through photoassociation effects,ultracold molecular vibrational levels has been realized.For high-resolution measurement,the stability of the absolute frequency of diode lasers with hyperfine transitions of caesium atoms,and the measurement of molecular rotational coefficients,this work takes advantage of trap loss spectroscopy technique which provides a new,non-destructive,and simple method for the investigation of Rydberg Atomic Spectroscopy.At the same time,this method can also be used to study the blockade effect of Rydberg atoms.In this paper,cesium atoms are used as experimental samples,and two oppositely propagated light beams are used to act on caesium atoms to form a stepped three-level system(6S_1/2?6P_3/2?D_3/2,5/2).Frequency of the weak detection light is locked to the transition of(6S_1/2?F=4??6P_3/2?F'=5?),while frequency of 510 nm laser is scanned to detect fine structure EIT spectrum of47D state;a magneto-optical trap is built to trap cesium atoms.The trap loss spectroscopy is applied to detect 47D state fine structure spectra.The main contents are:1.At room temperature,caesium atoms are excited from 6S_1/2/2 to 6P_3/2/2 by probe light of which the frequency is locked with help of ultra-stable cavity the locking result is less than or equal to 100 KHz.The transitions of 6P_3/2?D_3/2,_5/2/2 are excited by 510 nm coupling light,of which the frequency is scanned near nD state,and two PIDs are applied to stabilize the powers of two beams,and the locked power jitter is less than 1%.The ratios of transition strengths of 47D_5/2/47D_3/2/2 signals under different combinations of light polarizations were measured,and the Bloch equations of Rydberg EIT were theoretically solved.Considering the optical pumping effect,theoretical calculations and experimental results agreed with each other.2.Magneto-optical trap for trapping cesium atoms is introduced,including the technical device of the experiment in detail.The atomic density is measured through absorption imaging.3.The Trap loss spectroscopy of ultracold cesium atoms was studied.In the experiment,the spontaneous emission fluorescence of the transition 6P_3/2?6S_1/2/2 was collected by a lens,and then a continuous 510 nm excitation light was used to excite the atoms from 6P_3/2/2 state to the 47D Rydberg state.The changing of 6P_3/2?6S_1/2/2 fluorescence spectrum was observed,and the Bloch equation of the three-level system was theoretically solved.The theoretical and experimental results are in good agreement when the excitation light is weak.When the power of excitation light is increased to a certain value,there is an obvious deviation between theory and experiment due to the dipole blockade effect induced by strong interactions between Rydberg atoms.We have proposed a new method for studying the interaction between Rydberg atoms.The innovation of this article:1.Ratios of transition strength of 47D_5/2/47D_3/2/2 are measured by non-destructive detection method based on Rydberg EIT spectroscopy.The effect of different conditions such as polarizations and powers of lasers are investigated in detail.2.Trap loss spectroscopy was applied for Rydberg atoms detection to observe the fluorescence spectrum of the 6p3/2 state,and the trap loss signals which indicate the excitations of 47D5/2/47D3/2 states were obtained.When which indicate light was weak,the linear dependence of the ratio on power of excitation light provides a new method for studying interactions between Rydberg atoms.