Study On Correlation Characterization Of Anti-relaxation Characteristics And Surface Characteristics Of Alkali Metal Atomic Vapor Cell Anti-relaxation Coating

Alkali metal atomic vapor cell is the core component of quantum sensing devices such as atomic clock,atomic magnetometer and atomic gyroscope.The above applications of the alkali metal atomic vapor cell strongly depend on the long spin polarization lifetime of the alkali metal atoms.Spin-polarization lifetime of alkali-metal atoms will be reduced by the collisions between alkali-metal atoms and the wall of alkali-metal vapor cells.In order to prolong the spin-polarization lifetime of alkali metal atoms and improve the performance of atomic vapor cell,researchers have extensively studied the anti-relaxation methods of atomic vapor cells.At present,researchers typically use anti-relaxation surface coatings or buffer gases.However,with the development of miniaturization of quantum devices,anti-relaxation coating shows better application potential and development prospect than buffer gas,which stimulates researchers’ enthusiasm for anti-relaxation coating.At present,researchers have investigated the coating thickness,surface topography,coating composition,and relaxation time of coated alkali-metal vapor cells.Researchers seldom intuitively combine between the surface properties of the coating and the relaxation performance of the vapor cells directly.This paper has carried out the research work on the characterization of coating in alkali metal atomic vapor cell.The research work is as follows:In this study,we have studied the collision process between alkali metal atoms and the coating surface in the atomic vapor cell and the collision process between the probe tip and the coating surface under atomic force microscope.We analyzed the collision relaxation of alkali metal atoms and the energy dissipation during the driving process of probe tip,and found that these processes have similar elastic collision processes.Therefore,we put forward a method to measure the anti-relaxation performance of the coating,that is,the energy dissipation during the interaction between the probe tip and the sample surface is used to characterize the action of anti-relaxation coating surface adsorption energy on alkali metal atoms,thus realizing the characterization of the anti-relaxation coating.Moreover,we have made coated alkali metal vapor cell.We characterized the relaxation properties of alkali metal atoms in the coated vapor cell by building an optical platform.The energy dissipation of the coated surface was measured by AM-FM mode of atomic force microscope.In the experiment,the positive correlation between the energy dissipation in this collision process and the relaxation properties of alkali metal atoms in the coated vapor cell at different temperatures was verified.This discovery links the surface characterization with the relaxation property,and provides a new idea for the characterization of the anti-relaxation coating of alkali metal vapor cell.