Photonics Research, 2018, 6 (4): 040000A6, Published Online: Jul. 10, 2018
Photon-pair generation in a quadratically nonlinear parity-time symmetric coupler
Figures & Tables
Fig. 1. (a) Scheme of generation of photon pairs through the spontaneous parametric down-conversion in a nonlinear PT-symmetric coupler with linear absorption in the second waveguide. (b) Graphical representation of biphoton correlation function | ϕ n s , n i | 2 .
Fig. 2. Evolution of spatial signal and idler photon correlations between the two waveguide modes along the propagation direction (z ) depending on the phase mismatch (Δ β ) for different losses in the second waveguide γ s = γ i = γ . (a)–(c) γ = 0.5 below the PT-symmetry breaking threshold. (d)–(f) γ = 3 corresponding to PT-broken regime. For all plots, the coupling coefficients are C s = C i = 1 , C p = 0 , and pump is coupled to the first waveguide, A 1 ( z = 0 ) = 1 , A 2 ( z = 0 ) = 0 , and γ p = 0 .
Fig. 3. Normalized photon correlations, | ϕ n s , n i | 2 / ∑ n s ′ , n i ′ | ϕ n s ′ , n i ′ | 2 , versus the phase mismatch and loss in the second waveguide at the fixed propagation distance z = 10 . The pump is input to the (a)–(c) first [A 1 ( z = 0 ) = 1 , A 2 ( z = 0 ) = 0 ] or (d)–(f) second waveguide [A 1 ( z = 0 ) = 0 , A 2 ( z = 0 ) = 1 ]. Dashed lines indicate the linear PT-breaking threshold at γ PT = 2 C . Other parameters correspond to Fig. 2 .
Fig. 4. (a) Scheme of SFG in passive PT-symmetric nonlinear coupler with linear absorption in one waveguide. (b) Mismatch F between the SPDC and SFG depending on the input power P for | u n s ( z = 0 ) | 2 = | v n i ( z = 0 ) | 2 = P / 2 , plotted on a logarithmic scale. The propagation distance is z = 10 , signal and idler losses are equal γ s = γ i = 0.5 , there is no loss in the pump mode γ p = 0 , and the coupling coefficients are C s = C i = 1 , C p = 0 .
Diana A. Antonosyan, Alexander S. Solntsev, Andrey A. Sukhorukov. Photon-pair generation in a quadratically nonlinear parity-time symmetric coupler[J]. Photonics Research, 2018, 6(4): 040000A6.