Figure 2 | Scientific Reports

Figure 2

From: Coincidence measurements of two quantum-correlated photon pairs widely separated in the frequency domain

Figure 2

Theoretical calculation of collinear quasi-phase-matching condition for 780-nm pump laser as a function of the periodicity of the PPLN crystal (vertical axis). The bottom axis represents the SPDC signals (red curve) and the top the SPDC idlers (green curve). In the case of a periodicity of 21.5 µm, two pairs (Pair 1: 980 nm and 3810 nm; Pair 2: 1013 nm and 3390 nm) are simultaneously quasi-phase-matched under the same conditions.

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