Resumen: We demonstrate, both numerically and analytically, that it is possible to deterministically generate two photons from one and only one photon. We characterize the output two-photon field and make our calculations close to reality by including losses. Our proposal relies on real or artificial three-level atoms with a cyclic transition strongly coupled to a one-dimensional waveguide. We show that almost perfect down-conversion, with efficiency over 99%, is reachable using state-of-the-art waveguide QED architectures such as photonic crystals or superconducting circuits. In particular, we sketch an implementation in circuit QED, where the three-level atom is a transmon. Idioma: Inglés DOI: 10.1103/PhysRevA.94.053814 Año: 2016 Publicado en: Physical Review A 94, 5 (2016), 053814 [11 pp] ISSN: 2469-9926 Factor impacto JCR: 2.925 (2016) Categ. JCR: OPTICS rank: 21 / 92 = 0.228 (2016) - Q1 - T1 Categ. JCR: PHYSICS, ATOMIC, MOLECULAR & CHEMICAL rank: 11 / 35 = 0.314 (2016) - Q2 - T1 Factor impacto SCIMAGO: 0.0 - Atomic and Molecular Physics, and Optics