Fig. 1. Influence of beam quality on output performance of high power laser driver

Fig. 2. Influence of beam quality on energy output of high power laser driver

Fig. 3. Mathematical expression and measurement significance of light field

Fig. 4. Optical parameters to be measured in SG-Ⅱ

Fig. 5. Schematic of NIF wavefront measurement and control device^[12]

Fig. 6. Schematic of lightpath for ePIE algorithm

Fig. 7. Schematic of lightpath for 3PIE algorithm

Fig. 8. Principle and experimental results of highly tilted illumination imaging^[32]. (a) Schematic of highly tilted illumination imaging; (b) amplitude and (c) phase of pumpkin stem slice and (f) amplitude of resolution plate reconstructed by non-paraxial approximation algorithm; (d) amplitude and (e) phase of pumpkin stem slice and (g) amplitude of resolution plate reconstructed by paraxial approximation algorithm

Fig. 9. Principle and experimental results of single-shot 3PIE^[34-35]. (a) Imaging device of non-paraxial approximate single-shot 3PIE^[34];(b) diffraction spot array recorded by CCD; (c) amplitude and (d) phase of the first layer sample reconstructed by non-paraxial approximation algorithm; (e) amplitude and (f) phase of the second layer sample reconstructed by non-paraxial approximation algorithm; (g) (h) phase distribution of two layers phase resolution plate reconstructed by non-paraxial approximation algorithm; (i) imaging device of paraxial approximate single-shot 3PIE^[35]; (j) two-layer sample reconstructed by paraxial approximation algorithm

Fig. 10. Schematic of CMI

Fig. 11. Schematic of multi-step phase plate^[37]. (a) 3D and (b) 2D view of etched depth

Fig. 12. Flow chart of multimodal CMI^[37]

Fig. 13. Experimental reconstruction results of three-wavelength illumination^[37]. (A) Diffraction patterns recorded by CCD; reconstructed (a1)-(c1) amplitude and (a2)-(c2) phase of illumination beam at three wavelengths

Fig. 14. Schematic of CBS imaging technology^[41]

Fig. 15. Schematic of iterative process for BSEA coherent diffraction imaging^[43], f1, f2, f3, and f4 represent the focal points of four sub-beams, d⃗m represents the translation vector, and the top right illustration is the recorded diffraction spot

Fig. 16. Schematic of lightpath in the BSEA experiment^[43]

Fig. 17. Reconstruction capability comparison between BSEA and traditional CMI^[43]. (a) Diffraction patterns, (d) reconstructed resolution plate, and (g) corresponding experimental resolution recorded by traditional CMI; (b) diffraction pattern array recorded by the CBS imaging technique; (e) resolution plate reconstructed without using the average algorithm and (h) corresponding experimental resolution; using the averaging algorithm, (c) intensity distribution on the average plane, (f) reconstructed resolution plate, and (i) corresponding experimental resolution

Fig. 18. Application of CDI in phase measurement of large aperture optical elements^{[23, 50]}. (a) Schematic of measurement methods; (b) physical picture of CPP; (c) phase distribution measured by Zygo interferometer; (d) CPP phase distribution design diagram; (e) CPP phase distribution measured by ePIE; (f) physical image of array lens; (g) phase distribution of array lens measured by ePIE; (h) phase distribution of a single sublens; (i) intensity distribution of a single sublens at the focal spot

Fig. 19. Schematic for measuring the effect of alignment stress on the surface profile of optical element, and the effect of preload on the profile distribution of mirror^[39].(a) Device schematic; (b) amplitude and (c) phase of the transmitted light on the focusing lens surface without applying preload; (d) amplitude and (e) phase of the transmitted light on the focusing lens surface when preload is applied

Fig. 20. Surface profile of mirror under different preload forces measured by CMI method^[39]. (a)-(i) Change in the surface profile of mirror as the preload increases from 0 to 1 MPa

Fig. 21. Schematic of PIE full-field stress measurement technique^[54]

Fig. 22. Images of beam pattern under four polarization states^[54]. (a)-(d) Recorded diffraction patterns; (e)-(h) amplitude and (i)-(l) phase reconstructed by PIE technique

Fig. 23. Experimental stress distribution^[54]. (a) Isocline φ; (b) isometric δd; (c) isosum δs; (d) transverse force σx; (e) longitudinal force σy; (f) shear force σxy

Fig. 24. Focal spots recorded by Hardman sensor^[38]. (a) Focal spot recorded without pumping; (b) focal spot recorded with pumping

Fig. 25. Measurement of wavefront thermal distortion based on CDI^{[49, 57]}. (a) Schematic of measuring lightpath; (b)-(d) phase difference when the amplifier works at repetition frequency of 1, 5, and 7 Hz; (e)-(g) phase distribution after unwrapping

Fig. 26. Wavefront distribution of high-power laser measured by Fresnel phase inversion method^[21]. (a) Algorithm flow chart; (b)-(d) beam intensity distribution and reconstructed phase distribution under different energies, wherein (b) pump energy is 450 mJ and output energy is 42 mJ,(c) pump energy is 450 mJ and output energy is 2 mJ, (d) pump energy is 210 mJ and output energy is 2 mJ

Fig. 27. Phase inversion flow chart and experimental lightpath based on error reduction algorithm^[59]. (a) Flow chart; (b) experimental lightpath

Fig. 28. Measurement results of wavefront aberration^[59]. (a) Wavefront aberration measured by wavefront sensor; (b) wavefront aberration reconstructed by phase inversion algorithm; (c) comparison of wavefront aberration obtained by two methods

Fig. 29. Schematic of OMEGA EP focal spot diagnosis device and reconstruction algorithm^[22]. (a) Schematic of OMEGA EP terminal system focal spot diagnosis device, and WFS stands for wavefront sensor; (b) flow chart of phase reconstruction algorithm for wavefront diagnosis

Fig. 30. Experimental results of an improved sample beam focus prediction^[22]. (a) Focal spot directly recorded by far-field CCD; (b) initial FSD predicted value (cross-correlation is 0.71); (c) improved FSD predicted value (cross-correlation is 0.95)

Fig. 31. Schematic of wavefront measuring system^[40]. (a) Position and (b) structure diagram of wavefront measuring system in the SG-Ⅱ; (c) phase distribution of phase plate; (d) position relationship of wavefront measuring system and direct measurement device of focal spot distribution

Fig. 32. Focal spot intensity distribution^[40]. (a) Focal spot distribution obtained by geometric optics system; (b) focal spot distribution obtained by wavefront measurement system; (c) the result of digital saturation of Fig. 32(b)

Fig. 33. Focal spot distribution at different distances when the laser output energy is 600 J^[40]. (a) Distance to the minimum focal spot plane is -1.9 mm; (b) distance to the minimum focal spot plane is -1.14 mm; (c) distance to the minimum focal spot plane is -0.38 mm; (d) distance to the minimum focal spot plane is 0.38 mm; (e) distance to the minimum focal spot plane is 1.14 mm; (f) distance to the minimum focal spot plane is 1.9 mm

Fig. 34. Diffraction spots at six continuous moments when the air conditioning system was turned on, with an interval of 1 s, the complex amplitude distribution of six moments was reconstructed, and the phase distribution of six moments was compared^[61]

Fig. 35. Schematic of focal spot diagnosis for high power laser driver. (a) Schematic of NIF terminal optical component^[64]; (b) schematic of 3ω beam measurement^[63]; (c) diffraction pattern collected by experiment^[63]

Fig. 36. Reconstruction results of 3ω beam^[63]. (a) Amplitude and (b) phase distributions of phase mark; (c) amplitude and (d) phase distributions of near-field

Fig. 37. Comparison of CCD acquired images and reconstruction results,and intensity distribution on different planes near the focal spot, the number on the top of the image indicates the distance from focal plane^[63]. (a) CCD acquired image; (b) reconstruction result; (c) intensity distribution on different planes near the focal spot

Fig. 38. Schematic of self-reference time-domain shear nanosecond phase measurement^[70]

Fig. 39. Reconstruction results under different pulse widths^[70]. (a)-(d) Recorded time beat frequency signal; (e)-(h) reconstructed time phase distribution (red dashed line) and time intensity distribution recorded by oscilloscope (green solid line); (i)-(l) calculated spectral intensity distribution (blue solid line) and measured spectral intensity distribution (red dashed line)

Fig. 40. Schematic of measuring the space-time characteristics of femtosecond laser^[72]. (a) Schematic of CMISS; (b) spectral distribution of the source to be measured; (c) amplitude and (d) phase distribution of the phase mask; (e) recorded diffraction pattern

Fig. 41. CMISS reconstruction results and spatio-temporal coupling results^[72]. (a1)-(a5) Diffraction patterns of five different wavelengths, the numbers on the top of the pictures correspond to the wavelengths; reconstructed (b1)-(b5) amplitude and (c1)-(c5) phase; (d) reconstructed 3D amplitude contour of the spatiotemporal coupling of ultra-short pulses, and the projection on each side; reconstructed (e1)-(e3) amplitudes and (f1)-(f3) phases at different times, the numbers at the bottom of the pictures correspond to the time; (g1) two-dimensional amplitude distribution of x-t at y=512 and (g2) two-dimensional amplitude distribution of y-tat x=512

Fig. 42. Experimental lightpath of SUM-CDI ultrafast phase imaging^[78]

Fig. 43. Time series and reconstructed results of SUM-CDI^[78]. (a) Time relationship between detected light and pulsed light; (b) recorded diffraction patterns; (c) amplitude and (d) phase reconstructed by SUM-CDI, top number represents the time, left number represents the transmission time

Fig. 44. Physical diagram of phase uniqueness reconstructed by Ptychography algorithm^[26]. (a) Schematic of overlapping beam spots; (b) schematic of conjugate phases; (c) schematic of phase transformation caused by detecting beam translation, and arrows indicate the direction of movement; (d) complex space vector corresponding to the true phase; (e) complex space vector corresponding to the conjugate phase

Fig. 45. Spectra and complex amplitude of sample reconstructed by GDLM^[25]. (a) Initial complex amplitude and (b) spectral distribution of sample; (c) complex amplitude distribution of the transmitted light on phase mask; reconstructed (d) complex amplitude and (e) spectral distribution of the sample; (f) difference between the reconstructed and initial samples

Fig. 46. Comparison of reconstruction effects with different sources^[25]. (a) Phase mask; (b) pentagonal stop; (c) rectangular stop; (d)-(f) reconstruction results of three illumination functions; (g) error convergence curves under different illumination conditions