Adjustion And Optimization Of Two-dimensional Magneto-optical Trap Of Natural Abundance ⁴⁰K

Since the first realization of Bose-Einstein condensate in 1995,preparation and related research of ultracold heteronuclear diatomic molecules has become a new field of atomic,molecular and optical physics.23Na40K,with chemical stability in the ground state and great electrical dipole moment,we choose it as our research object,and expect to avoid chemically unstable phenomenon like other molecules.Our main purpose of experimental work is the preparation of 23Na40K bose-Fermi quantum mixed gas and process related research work on this basis.To realize hybrid quantum gas,the first step is to realize the rapid loading and a large number of magneto-optical trap atomic number.This paper mainly introduces using potassium source of natural abundance to adjust and optimize the MOT atomic number of 40K.In the preparation of light path system,heating system and production of common circuits that used in the experiment,due to the 40K of natural abundance is only 0.012%,and the purificatory potassium source is very expensive,different from 23Na using Zeeman slower to prepare magneto-optical trap atoms,40K using a combination of magneto-optical trapping in two dimensions and Doppler cooling in the third dimension to precool and collect magneto-optical trap atoms.Because the natural abundance of 39K is 93.258%,and frequency shift of laser between 39K and 40K can be transformed by using the acousto-optic modulator,we test our 2D+-MOT vacuum system and laser system through the adjustion of magneto-optical trap of 39K.Then,after adjusting and optimizing the corresponding parameters of 40K,including the vapor pressure,optical power,detune and gradient magnetic field,we realize the maximum number of three-dimensional magneto-optical trap atoms of 40K is 5×106,loading rate is 1.5×105 atoms/s.At the same time,in order to increase the number of 2D+-MOT atoms of 40K,an electro-optical modulator with stable output of about 12MHz was successfully obtained.Since the normal mechanical switch was too slow,the optical switch with 500V adjustable stabilized voltage source is designed and manufactured,which could be used for further experimental which atomic be cooling in the optical trap phase.