Spectroscopy of a singly trapped $^{25}$Mg$^{+}$ ion

We will present and discuss results from a measurement of the linewidth and hyperfine A constant of the $^{2}$P$_{1/2}$ excited state in $^{25}$Mg$^{+}$.\space We trapped the ion in a linear Paul trap and laser cooled it using the $^{2}$S$_{1/2}$ $\rightarrow$ $^{2}$P$_{3/2}$ transition.\space We optically pumped the ion into the F=3, m$_{F}$=-3 ground state and weakly probed it with a tuneable fiber laser that was scanned to drive the ion from the ground state to the F=3 and F=2 manifolds of the $^{2}$P$_{1/2}$ state. The final state of the ion was determined by by counting fluorescence (or the lackthereof) from the $^{2}$S$_{1/2}$(F=3,m$_{F}$=-3) $\rightarrow$ $^{2}$P$_{3/2}$(F=4,m$_{F}$=-4) cycling transition with a photomultiplier tube.\space Using this method we measured the linewidth with negligible Doppler contributions at different laser intensities and varying magnetic fields.