Mid-infrared Spectrally Pure Single-Photon States Generation from 22 Nonlinear Optical Crystals

Figure 4

(a, e, i) are the JSAs; (b, f, j) are the spectra; and (c, d, g, h, k, l) are the HOM interference patterns. The FWHM of the spectra for the signal and the idler, the visibility (V), and the FWHM of two-fold and four-fold HOM interference are shown in the figures. The parameters of  mm and  nm (FWHM = 6.66 nm),  mm and  nm (FWHM = 13.32 nm),  mm and  nm (FWHM = 18.32 nm) are adopted for , LGSe, and PMN-0.38PT, respectively. Note that for all the calculations of purity, we use a grid size of  200 for all the JSAs.

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