Dynamically reconfigurable polarization-entangled photon-pair generation in an anisotropic resonant photonic time...

We theoretically investigate dynamically reconfigurable polarization-entangled photon-pair generation in an anisotropic resonant photonic time crystal. Periodic switching between two anisotropic resonant states produces Floquet coupling among the HH, HV, VH, and VV pair-generation channels. An eight-dimensional Bogoliubov-de Gennes model shows that the modulation-axis angle and relative temporal phase enable switching among |Φ⁺⟩-,|Φ^-⟩-, and |Ψ⁺⟩-like outputs without altering the structure. At a representative operating point, the pair brightness reaches N_pair=1.34, with a concurrence of 0.963 and a Bell-state fidelity of 0.982. Exact time-ordered calculations agree closely with the rotating-wave approximation. The proposed platform provides a compact route toward programmable entangled-photon generation and time-modulated quantum photonics.