Abstract: A solar heater has a light collector which collects light incident on the light collector into a beam that extends along a beam axis. A plurality of thermally conductive plates is arranged along the beam axis, each of the plates having an aperture on the beam axis. For each plate, the aperture of the plate is smaller than apertures of all plates disposed between each plate and the light collector along said beam axis. A fluid pathway is associated with one or more of the plates for transferring heat to a fluid in the fluid pathway. In a related method of heating a fluid, light rays are collected into a beam and passed through progressively smaller apertures in a plurality of serially arranged plates such that a portion of the beam is incident on each one of said plates. The fluid is thermally contacted with the plates.