A possible redefinition of candela using light shift

Candela is one of the seven base units in the SI. The units of time and length have been defined in quantum method and the others of the base units have the potential to be redefined in quantum method or on fundamental constants, except candela. With the accuracy of measurement and application increasing, the requirement of a more accurate definition of candela is becoming urgent. In this paper, we propose a quantum method to redefine the unit of luminous intensity candela. An example shows that the accuracy of candela under the new definition can reach even better than 10^-6 with the help of Rb atomic clock.