(color online). Three dimensional TBFI refractive index reconstructions of polystyrene spheres. (a) Enface bright field image of 0.1 μm polystyrene sphere (n = 1.597, imaging wavelength λ = 540 nm), suspended in fluoromount G (n = 1.4) (b) corresponding refractive index map. (c) Cross sectional image of 0.1 μm sphere, (d) corresponding refractive index map. (e) Enface bright field image of 2.8 μm polystyrene sphere suspended in glycerol (n = 1.474), (f) corresponding refractive index map, (g) cross sectional bright field image of 2.8 μm sphere, (h) cross sectional refractive index map.