title: Weak-signal conversion from 1550 to 532  nm with 84% efficiency.
abstract: We report on the experimental frequency conversion of a dim, coherent continuous-wave light field from 1550 to 532 nm with an external photon-number conversion efficiency of (84.4±1.5)%. In contrast to previous works, our conversion efficiency value incorporates all losses before the photoelectric detection, including those introduced by frequency filters. We used sum-frequency generation, which was realized in a standing-wave cavity built around a periodically poled type I potassium titanyl phosphate (PPKTP) crystal, pumped by an intense field at 810 nm. Our result is in full agreement with a numerical model. For optimized cavity coupler reflectivities, it predicts a conversion efficiency of up to 93% using the same PPKTP crystal.
authors: Aiko
authors: A
authors: Samblowski
authors: Christina E
authors: CE
authors: Vollmer
authors: Christoph
authors: C
authors: Baune
authors: Jaromír
authors: J
authors: Fiurášek
authors: Roman
authors: R
authors: Schnabel