Parametric resonances of ions in an ion trap

Vaibhav Mahendrakar

The natural oscillation frequency (f) of a periodic system depends on different parameters of the system (For eg. In case of a simple pendulum, the parameters are the length and acceleration due to gravity). Periodic modulation of these parameters, at a frequency 2f/n where n is a positive integer, acts as an external drive to the oscillator and causes the amplitude of oscillation to increase even at small modulation amplitudes. This phenomenon is known as “Parametric resonance”.

In this talk I will discuss how the method of parametric resonance/excitation is used to determine the natural oscillation frequency of ions in an ion trap. We use this method to determine the oscillation frequency of trapped 7Li+ ions which are loaded in our linear Paul trap by photoionization of 7Li MOT atoms. Additionally, using parametric excitation we determine the Q/M ratio of an unknown ion which gets produced during the 2S->2P->3S excitation of Lithium MOT atoms.