Photoionization cross sections of the 5S${}_{1\mathrm{/}2}$ and 5P${}_{3\mathrm{/}2}$ states of Rb in simultaneous magneto-optical trapping of Rb and Hg

We report the measurement of the photoionization cross sections of the 5S${}_{1\mathrm{/}2}$ and 5P${}_{3\mathrm{/}2}$ states of ${}^{87}$Rb in a two-species Hg and Rb magneto-optical trap (MOT) by the cooling laser for Hg. The photoionization cross sections of Rb in the 5S${}_{1\mathrm{/}2}$ and 5P${}_{3\mathrm{/}2}$ states at 253.7~nm are determined to be $1_{-1}^{+4.3}\times {10}^{-20}{\text{cm}}^2$ and $4.63(30)\times {10}^{-18}{\text{cm}}^2$, respectively. To measure the 5S${}_{1\mathrm{/}2}$ and 5P${}_{3\mathrm{/}2}$ states fractions in the MOT we detected photoionization rate of the 5P${}_{3\mathrm{/}2}$ state by an additional 401.5~nm laser. The photoionization cross section of Rb in the 5P${}_{3\mathrm{/}2}$ state at 401.5~nm is determined to be $\text{1.18(10)}\times {10}^{-17}{\text{cm}}^2$.