Abstract: As the core technology and physical reference system of quantum frequency standards and quantum computing,ion trap has important application prospect and plays an important role in the fields of precision measurement,quantum computing,and high precision positioning and navigation.An ion preparation and trap system based on Paul ion trap is proposed for photo-ionization,ion-trap and laser Doppler cooling.The multi-channel and multi-wavelength laser frequencies are stabilized with a digital PID control method.In the experimental system,the weak fluorescence signal of single-ion is detected representing the single-ion is trapped.The laser frequency drift is stabilized from 500 MHz to ±0.8 MHz.The ion temperature reaches 5.53 mK via laser cooling,approaching the Doppler cooling limit.

Key words: Ion trap, laser Doppler cooling, Photo-ionization, Optical frequency standards