Figure 1

Experimental arrangement of lensless Fourier ghost imaging with pure far-field correlated thermal light.Reuse & Permissions

Figure 2

Horizontal coherent length of speckle patterns vs distance from the pseudothermal source to the CCD camera. (a) Horizontal coherent length in a 0 order beam. The square scatters are the measured coherent length for the free propagating radiation without the grating in the path, and the thin solid line is the linear fit; the dot symbol and dashed line represents the result of the Van Cittert–Zernike equation when $z_1=59\mathrm{mm}$, the triangle symbol and dotted line represent $z_1=91\mathrm{mm}$, and the diamond symbol and bold solid line represent $z_2=159\mathrm{mm}$. These four lines are parallel within experimental approximation. Corresponding to (a) the lines of different style represent the coherent length in the $+1$ order beam for each $z_1$ in (b), and the square scatters and the linear fit thin solid line is a copy component of (a).Reuse & Permissions

Figure 3

Experimental measurement of angular spectrum correlation in the far field. (a) is a frame of the far-field speckle distribution in a $+1$ order beam. (b) is the normalized mutual intensity fluctuation correlation between $\pm 1$ order beams, on the right upper side is the correlation of far-field speckle, and the Gaussian curve is the cross term of the correlation, where $\sigma =9.187$ denotes the Gaussian fitting parameter. Correspondingly, (c) is the normalized autointensity fluctuation correlation of the 0 order beam, and (d) is the normalized mutual intensity fluctuation correlation between 0 and $+1$ order beams.Reuse & Permissions

Figure 4

Fourier-transform ghost image of a double slit between $\pm 1$ order beams. (a) is the Fourier-transform ghost image illuminated directly by the laser with a $f=100\mathrm{mm}$ lens. (b) is the Fourier-transform ghost image on the CCD plane. (c) is the normalized cross section of (a) and (b), where the solid line is the laser-illuminating image, dispersive squares are the experimental correlated data, and the dashed line is the fitting curve.Reuse & Permissions

Figure 5

Fourier-transform ghost image of a griddle between $\pm 1$ order beams. (a) is the Fourier-transform ghost image of the griddle illuminated directly by the laser with a $f=100\mathrm{mm}$ lens. (b) is the corresponding Fourier-transform ghost image, where only low spatial frequencies are drawn out.Reuse & Permissions

Figure 6

Fourier-transform ghost image of a double slit between 0 and $+1$ order beams. (a) is the correlated image on the CCD plane. (b) is the normalized cross section of (a), where the squares are the experimental correlated data and the solid line is the fitting curve.Reuse & Permissions