We demonstrate the simultaneous magneto-optical trapping (MOT) of Rb and Sr and examine the characteristic loss of Rb in the MOT due to photoionization by the cooling laser for Sr. The photoionization cross section of Rb in the $5P_{3/2}$ state at 46
1 nm is determined to be $1.4(1)times10^{-17}$ cm$^2$. It is important to consider this loss rate to realize a sufficiently large number of trapped Rb atoms to achieve a quantum degenerate mixture of Rb and Sr.
We propose a new kind of spin manipulation method using a {it fictitious} magnetic field generated by a quasi-electrostatic field. The method can be applicable to every atom with electron spins and has distinct advantages of small photon scattering r
ate and local addressability. By using a $rm{CO_2}$ laser as a quasi-electrostatic field, we have experimentally demonstrated the proposed method by observing the Rabi-oscillation of the ground state hyperfine spin F=1 of the cold $rm{^{87}Rb}$ atoms and the Bose-Einstein condensate.
