Pump photon (frequency ω_p) splitting in a χ⁽²⁾ nonlinear crystal into signal and idler photons (ω_p = ω_s + ω_i, k_p = k_s + k_i). Standard source of entangled photon pairs for Bell tests, quantum cryptography, and heralded single photons.
Pump photon (frequency ω_p) splitting in a χ⁽²⁾ nonlinear crystal into signal and idler photons (ω_p = ω_s + ω_i, k_p = k_s + k_i). Standard source of entangled photon pairs for Bell tests, quantum cryptography, and heralded single photons.