Figure 2

Holographic reconstruction of a spongila spicule. Reconstruction of a hologram recorded in coherent mode. The object is a siliceous three-pronged spongilla spicule. (a) absolute value of the reconstruction amplitude, (b) wrapped phase map of the optical thickness of the object relative to the mounting medium (black = -π/2 + n 2π ; gray = n 2π ; white = π/2 + n 2π), (c) unwrapped phase map (the color code indicates the phase in radians), (d) 3D phase profile of the object.