Research On The Key Technologies Of Compact-sized Strontium Laser Cooling System

Strontium(Sr)-based optical lattice clock and atomic interferometry can be used in the field of high precision and high accuracy time-frequency standard and quantum metrology,embedded with an innate advantage in the regime of space application.The first step to explore the space application of cold atoms is to minimize the size of the system.This thesis studies the key technologies in the realization of compact-sized strontium laser cooling and atoms trapping system.The contents of this thesis are summarized as follows:(1)Studied the physical characteristic and energy level structure of Sr atoms,analyzed the theory of the effect of light field on atoms,the principle and process of Sr laser cooling and trapping using Doppler cooling theory.The thermal atoms are decelerated by first-stage cooling and captured in a Blue magneto-optical trap(Blue MOT),and then are trapped in a Red MOT as the second-stage cooling.Finally,optical lattice is introduced to weaken the interaction between the cold atoms.(2)Design and construction of the vacuum and physical system of the compact-sized Sr laser cooling and trapping system.The requirements of the vacuum system are analyzed,the materials and devices that meet the vacuum requirements are selected,and the extraction and maintenance of the vacuum are completed by the molecular pump-ion pump system.The physical apparats are designed to meet the compact size requirements,including the current heating Sr source,permanent magnet Zeeman slower and built-in coil 3D magneto-optical trap.The physical system is built and tested.(3)Design of the compact-sized Sr atomic laser cooling optical system and the construction of the first-stage cooling light path are completed.Requirements of compactsized Sr atomic cooling lasers are analyzed,the design of the first-stage cooling,secondstage cooling and optical lattice light path are design.For the first-stage cooling,achieved 461 nm laser frequency locking by thermal atomic beam,completed first-stage cooling light path and conducted atomic cooling experiments.(4)Complete the design,realization and testing of ring-shaped permanent magnet Zeeman slower.Through the calculation of the parameters of the Zeeman deceleration magnetic field,the structure and parameters of the permanent magnet Zeeman slower are designed and the production and assembly of the permanent magnet slower are achieved.The slowing effect of Zeeman slower is tested.The ring-shaped permanent magnet Zeeman slower can decelerate the Sr atoms from the initial speed of 450 m/s to 100m/s,the deceleration efficiency is about 15%.