Yonglei Liu, Yahong Chen, Fei Wang, Yangjian Cai, Chunhao Liang, Olga Korotkova. Robust far-field imaging by spatial coherence engineering[J]. Opto-Electronic Advances, 2021, 4(12): 210027-1

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- Opto-Electronic Advances
- Vol. 4, Issue 12, 210027-1 (2021)

Fig. 1. Variation of the modulus of DOC |μ | of a CGCSM beam with the propagation distance z after the focusing lens, with the CP strength factor (a1 −a4 ) u = 0 mm−2, (b1 −b4 ) u = 2 mm−2, (c1 −c4 ) u = 10 mm−2, and (d1 −d4 ) u = 70 mm−2. The parameters are set as λ = 532 nm, δ 0 =0.5 mm and n =1.

Fig. 2. Theoretical results of the modulus of the DOC |μ | at different propagation distances z after the lens with the CP strength factor u =−60 mm−2 . The inserted letter “S” in (a) is adopted as the power spectral density P (v ) function.

Fig. 3. Schematic diagram of the experiment setup for generation of Schell-model beams with a controllable CP structure, measurement of the modulus of the DOC in the far field propagation in free space as well as in turbulent atmosphere . Laser, a Nd:YAG laser with wavelength 532nm; M, mirror; BE, beam expander; SLM1, SLM2, spatial light modulator; RGGD, rotating ground glass disk; L1, L2, L3, L4, L5, L6, thin lenses with the identical focal length f =250mm; GAF, Gaussian amplitude filter; BS, beam splitter; CA, circular aperture; SP, source plane; CCD, charge-coupled device; HP, hot plate; PC1, PC2, PC3, personal computers.

Fig. 4. (a −d ) Experimental results of the modulus of the DOC |μ | in the focal plane with different strength factors u. (e −h ) The modulus of the DOC |μ | at different propagation distances z after the lens with the CP strength factor u =−60 mm−2.

Fig. 5. Experimental results of the modulus of the DOC |μ | in the focal plane at different temperatures of the HP . The strength factor of the CP is u =−60 mm−2. T =0 °C stands for the free space case.

Fig. 6. Experimental results of the dependence of the quality of the recovered image on the strength factor u in the focal plane in free space .

Fig. 7. (a −c ) Simulation results of the reconstructed image in turbulence of different strength and with different CP strength factor u. (d −f ) Experimental results of the reconstructed image at different temperatures with u =−60 mm−2.

Fig. 8. (a ) A typical instantaneous intensity captured by the CCD. (b ) Experimental results of the recovered image through the area surrounded by the yellow dashed square shown in subplot (a) covering 1440×1440 pixels. (c ) The recovered image through the area surrounded by the red dashed square shown in subplot (a) covering 500×500 pixels.

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