A mechanical rotor capable of generating rotary mechanical power by the effects of light impinging on the parallel surfaces of multiple vanes. The light activated rotor utilizes a number of vanes affixed to a hub rotatable around an axle, with the vanes typically in a perpendicular arrangement to the axle. Each vane is separated into a first surface and a second surface with the first and second surface generally side-by-side and sharing a common boundary. Additionally, the first and second surfaces have differing emissivities for incident, impinging light. When the light activated rotor is illuminated with a radiant flux, the differing emissivities of the first and second surfaces produce a temperature gradient across each vane and generates a thermal creep force on the vane, producing rotation of the hub and vanes and providing a rotary mechanical power. The rotary mechanical power can be transferred to other devices for use. The Light Activated Rotor has particular applicability as a microelectromechanical system (MEMS) device