Fig. 1. OPT forward measurement model. (a) Forward QPI measurement process; (b) illustration of Fourier-slice theorem

Fig. 2. ODT forward measurement model

Fig. 3. Illustration of Fourier diffraction theorem

Fig. 4. Frequency domain mapping under different rotation modes. (a) Illustration of sample rotation; (b) illustration of incident wave rotation; (c) frequency domain mapping of one single measurement; (d) frequency domain mapping of sample rotation mode; (e) frequency domain mapping of incident wave rotation mode

Fig. 5. Comparison of three-dimensional refractive index distribution quantitative imaging results of hepatocyte cells^[64]. (a) Direct inversion; (b) non-negativity constraint; (c) EP regularization; (d) TV regularization

Fig. 6. ODT measurement based on digital holography. (a) Sample rotation; (b) incident wave rotation

Fig. 7. Representative ODT imaging results based on interference measurement^[129]. (a) Bright-field image of a normal colon tissue slice stained with H&E; (b) an unstained colon tissue slice imaged with ODT; (c)(e) three-dimensional refractive index quantitative images of 100 μm thick tissue slices, (c) pancreas, (d) large intestine, (e) small intestine

Fig. 8. Representative ODT imaging results based on non-interference measurement^[82]. (a) Quantitative refractive index image of HeLa cells at z＝2.93 μm; (b1)(b3) results of three HeLa cells at different depths; (c1)(c3) rendered results of three HeLa cells