Archie David Kao (born December 14, 1969) is an American actor and producer. He is best known for his American roles as Sheldon Jin on Chicago P.D., Archie Johnson on CSI, Sebastian in Snow Flower and the Secret Fan, and Kai Chen / Blue Power Ranger on the original 1993 series Power Rangers as well as the specials Power Rangers Lost Galaxy: The Power of Teamwork Overcomes All and Power Rangers in 3D: Triple Force!.