LAUSR

$$^{171} \mathrm{Yb}^{+}$$ ions were trapped in a quadrupole ion trap. A mode-locked pulse laser at 355 nm was used to generate a frequency comb to drive a Raman transition between the ground hyperfine qubit states of the Doppler cooled ion. Qubit transitions were driven in co-propagating and counter propagating laser beam geometries. In the co-propagating geometry, the coherence time and the fidelity of gate operations were obtained. By taking advantage of the phonon number sensitivity of the Rabi frequency in the counter-propagating geometry, we measured the center of mass temperature of the trapped ion near the Doppler limit which can be used for general thermometry in the ion trap experiment.