A method, an inspection system and a sensing unit. The sensing unit may include a light recycling optics and a photon to electron converter. The photon to electron converter is configured to receive a first light beam emitted from the object and impinging on the partially reflective surface at a first oblique angle, absorb a first portion and reflect a second portion of the first light beam to provide a first reflected beam. The light recycling optics is configured to redirect, towards the partially reflective surface, one or more reflected beams reflected from the partially reflective surface to provide one or more recycled beams. The photon to electron converter is configured to output electrons that represents an absorbed portion of the input light beam and an absorbed portion of each one of the one or more recycled beam.