Fig. 1 Timeline of LN as a photonic material[22]

Fig. 2 Time dependence of diffraction efficiency of LN:V crystals[66]

Fig. 3 Comparison between the local lattice distortions of VLi, NbLi and the bulk LiNbO3 calculated by spin-polarized HSE06[69] (a) Lattice of ${\text{V}}_{\text{Li}}^{4+}$; (b) Lattice of ${\text{Nb}}_{\text{Li}}^{4+}$; (c) Lattice of ${\text{V}}_{\text{Li}}^{3+}$; (d) Lattice of ${\text{Nb}}_{\text{Li}}^{3+}$; (e) Lattice of ${\text{V}}_{\text{Li}}^{2+}$; (f) Lattice of ${\text{Nb}}_{\text{Li}}^{2+}$; (g) Lattice of bulk lithium niobate. Red balls refer to O, green balls refer to V, grey balls refer to Nb, and white balls refer to Li

Fig. 4 Photorefractive properties of CLN and LN:V, Mg crystals measured at the wavelength of 532 and 488 nm[70] (a) Diffraction efficiency; (b) Response time

Fig. 5 OH− absorption spectra and light energy transfer curves for two-beam coupling of CLN, LN:V and LN:Mg, V crystals[70] (a) OH− absorption spectra; (b) Light energy transfer curves

Fig. 6 Angular scans for Nb- and W-RBS along the <$01\overline{1}0$>, <$02\overline{2}1$>, <$11\overline{2}0$> axial directions, and computer simulation of the occupancy of Nb and W ions in the direction of <$02\overline{2}1$>[73-74] (a) Angular scans; (b) Occupancy simulation

Fig. 7 Time dependence of diffraction efficiency of CLN:W crystals measured at the wavelength of 532 nm[76] (a) CLN:W0.5in; (b) CLN:W2.0in; (c) CLN:W0.5out; (d) CLN:W2.0out; (e) CLN:W3.0in

Fig. 8 Time dependence of diffraction efficiency of CLN:W crystals measured at the wavelength of 488 nm[76] (a) CLN:W0.5in; (b) CLN:W2.0in; (c) CLN:W0.5out; (d) CLN:W2.0out; (e) CLN:W3.0in

Fig. 9 Photorefractive properties of LN:Mo crystals from UV to visible[77] (a) Diffraction efficiency; (b) Response time

Fig. 10 Formation energies of LN:Mo[78]

Fig. 11 Band structure diagrams of different defect pairs in LN:Mo[78]

Fig. 12 Local lattice distortion of (a) pristine and (b) MoNb+, (c) MoNb0, (d) MoNb− point defects[78]

Fig. 13 Photorefractive properties of LN:Mo, Mg and LN:Mo, Zr with different concentrations from UV to the visible bands[80] (a) Diffraction efficiency; (b) Response time; (c) Refractive index change; (d) Sensitivity

Fig. 14 (a) Swing curve and (b) FWHM values at different positions on wafers of LN:U0.6[93]

Fig. 15 XPS spectra of LN:U0.6 and the fitting peaks[93]

Fig. 16 Photorefractive properties of LN:U with different concentrations in the visible band[94] (a) Diffraction efficiency; (b) Refractive index change; (c) Response time; (d) Sensitivity

Fig. 17 Photorefractive parameters of CLN, LN:U0.6, LN:U0.6, In2.0, and LN:Fe0.3[95] (a) Diffraction efficiency; (b) Response time; (c) Refractive index change; (d) Sensitivity

Fig. 18 Photorefractive properties of LN:U, Mg with different concentrations[96] (a) Diffraction efficiency and sensitivity; (b) Response time and refractive index modulation

Fig. 19 Transmission spectra of LN:Tb under UV irradiation and temporal evolution of 313 nm induced absorption[104] (a) Transmission spectra; (b) Induced absorbance

Fig. 20 Photorefractive properties of LN:Bi with different concentrations[106] (a) Diffraction efficiency and refractive index change; (b) Response time and sensitivity

Fig. 21 Photorefractive properties of LN:Bi, CLN, and LN:Bi, Mg with different Mg concentrations[107] (a) Diffraction efficiency and refractive index change; (b) Response time and sensitivity

Fig. 22 Holographic images during display (at 60 Hz)[109] (a) Rhythmic gymnastics; (b) Karate kumite; (c) Diving; (d) Baseball; (e) Olympic rings; (f) Basketball; (g) Athletics; (h) Shooting; (i) Surfing