Molecular Dynamics Simulation And Experiment Of The Cooling Effect Of Trapped Ion By Pulsed Laser

Because of its important role in basic physics and military and civilian fields,the optical clock technology has attracted people’s attention for a long time.With the development of related science and technology,optical frequency standard has made rapid development in recent decades,new candidate systems for optical clocks have been proposed,such as highly-charged-ion-based(HCI)optical clocks,nuclear-based optical clocks,etc.Due to the reference transitions for these clocks are insensitive to the external field,these clocks are considered to be one of the next generation optical clocks with higher-precision.Among them,the uncertainty of the 27Al+optical clock implemented by the National Institute of Standards and Technology(NIST)has reached the lowest level of 9.4 × 10-19.However,for the above-mentioned clock candidates,the wavelengths of the cooling lasers are often in the deep ultraviolet(DUV)range,take 27Al+as an example,the nature width of the transition between 1S0→1 P1 is 224 MHz,which is an ideal choice for laser cooling,while no CW laser with wavelength less than 170 nm has been reported yet.This makes people have to indirectly cool the target particles by means of technologies such as sympathetic cooling,which not only increases the complexity of the experiment,but also brings additional uncertainty.In 2017,the Technical Institute of Physics and Chemistry CAS developed the world’s first 167nm laser through a frequency doubling scheme.However,due to the bottleneck of related technologies,only pulsed laser has been achieved.In this context,the research on pulsed laser Doppler cooling is particularly important.This thesis introduces the author’s main work during the master’s period.The main content of the thesis is as follows:1.Fokker-Planck equation is used to describe the Doppler cooling of 40Ca+and 27Al+in the case of short pulses,numerical calculations are carried out,relationship between Doppler cooling limit and related parameters are given;2.An optimized Molecular Dynamics Simulation program was constructed to make it suitable for a wider range of application scenarios in ion trap physics,including but not limited to pulsed laser Doppler cooling and multi-ion sympathetic cooling;3.Using the optimized Molecular Dynamics Simulation program,combined with related experiments,the possibility of direct cooling of 27Al+by pulsed laser,the feasibility of driving 40Ca+ ions away after sympathetic cooling 27Al+,etc.were explored.