title: Second-harmonic generation in periodically poled bulk Rb-doped KTiOPO₄ below 400 nm at high peak-intensities.
abstract: We demonstrate that bulk Rb-doped KTiOPO₄ (RKTP) shows improved susceptibility to gray-tracking compared to flux-grown KTiOPO₄ . We show high-fidelity periodic poling of 1 mm thick RKTP with a period of 3.18 µm for second harmonic generation at 398 nm with a normalized conversion efficiency of 1.79%/Wcm. The crystal is used to frequency-double 138 fs-long pulses with an efficiency of 20% and a peak intensity of 560 MW/cm² without visible gray-tracking signs. We demonstrate that two-photon absorption is the predominant mechanism limiting the SHG efficiency in this spectral range at high peak powers and high repetition rates.
authors: Department of Applied Physics, Royal Institute of Technology, Roslagstullsbacken 21, 10691 Stockholm, Sweden. az@laserphysics.kth.se
authors: Andrius
authors: A
authors: Zukauskas
authors: Valdas
authors: V
authors: Pasiskevicius
authors: Carlota
authors: C
authors: Canalias
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D053844:Lasers, Solid-State; D008027:Light; D008422:Materials Testing; D010710:Phosphates / Q000737:chemistry* / Q000528:radiation effects*; D012413:Rubidium / Q000737:chemistry* / Q000528:radiation effects*; D012542:Scattering, Radiation; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D010710:Phosphates; C064806:potassium titanylphosphate; D014025:Titanium; D012413:Rubidium