Photosynthesis lighting system comprising: a curved beam steering element for directing a beam of illumination to at least one plant； a motor for rotating the beam steering element to select different locations of the at least one plant to be illuminated by the illumination beam； motorized optical focusing means for adjusting an area size for each of the locations, thereby determining an area of the at least one plant to be illuminated； and a controller for controlling the motor and the motorized focusing optical means to supply equal lighting energy to each unit area of the at least one plant and to illuminate no other area.
