NOVELTY - A solar energy harvesting device (100) comprises lightguide structure (110) consists of opposing, locally parallel 1st boundary surface (112) and 2nd boundary surface (114) and material layer (115) with a stimuli-responsive material (SRM) (116) that is evenly distributed throughout material layer which is disposed between 1st and 2nd boundary surfaces, solar radiation concentrating part (120) for concentrating solar radiation directed on device such that solar radiation is concentrated at focal point disposed inside material layer, and solar energy receiver (150).    USE - A solar energy harvesting device (claimed).    ADVANTAGE - Manufacturing costs and lighting costs are reduced, undesirable high radiance area and excessive solar heating are prevented, and fluctuations of lighting level are attenuated.    DETAILED DESCRIPTION - A solar energy harvesting device (100) comprises lightguide structure (110) consists of opposing, locally parallel 1st boundary surface (112) and 2nd boundary surface (114) and material layer (115) with a stimuli-responsive material (SRM) (116) that is evenly distributed throughout material layer which is disposed between 1st and 2nd boundary surfaces, solar radiation concentrating part (120) for concentrating solar radiation directed on device such that solar radiation is concentrated at focal point disposed inside material layer, and solar energy receiver (150) disposed in fixed relationship to lightguide structure. SRM is characterized such that all SRM disposed in material layer assumes 1st state when 1st amount of concentrated solar radiation at focal point is below a predetermined 1st level and a portion (116-2) of SRM disposed on focal zone adjacent to focal point changes from 1st state to 2nd state when concentrated solar radiation at focal point increases from 1st amount to predetermined 2nd amount while remaining portion (116-1) of SRM disposed outside of focal zone remains in 1st state, wherein 2nd state is more opaque than 1st state such that concentrated solar radiation is reflected by portion in 2nd state and transmitted through remaining portion of SRM in 1st state, and solar energy receiver is positioned to receive at least a portion of redirected concentrated solar radiation.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional diagram of a solar energy harvesting device.    Solar energy harvesting device (100)    Lightguide structure (110)    1st boundary surface (112)    2nd boundary surface (114)    Material layer (115)