title: Optimization of single-cycle terahertz generation in LiNbO3 for sub-50 femtosecond pump pulses.
abstract: We compare different tilted-pulse-front pumping schemes for single-cycle THz generation in LiNbO(3) crystals both theoretically and experimentally in terms of conversion efficiency. The conventional setup with a single lens as an imaging element has been found to be highly inefficient in the case of sub-50 fs pump pulses, mainly due to the resulting chromatic aberrations. These aberrations are avoided in the proposed new setup, which employs two concave mirrors in a Keplerian telescope arrangement as the imaging sequence. This partially compensates spherical aberrations and results in a ca. six times higher conversion efficiency in the case of 35-fs optical pump pulse duration compared to the single-lens setup. A THz field strength of 60 kV/cm was obtained using 0.5 mJ pump pulses. The divergence of the THz beam has been found experimentally to depend on the pump imaging scheme employed.
authors.affiliation: Institut für Kernphysik, Goethe Universität Frankfurt am Main, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany. kunitski@atom.uni-frankfurt.de
authors.forename: Maksim
authors.initials: M
authors.lastname: Kunitski
authors.forename: Martin
authors.initials: M
authors.lastname: Richter
authors.forename: Mark D
authors.initials: MD
authors.lastname: Thomson
authors.forename: Arno
authors.initials: A
authors.lastname: Vredenborg
authors.forename: Jian
authors.initials: J
authors.lastname: Wu
authors.forename: Till
authors.initials: T
authors.lastname: Jahnke
authors.forename: Markus
authors.initials: M
authors.lastname: Schöffler
authors.forename: Horst
authors.initials: H
authors.lastname: Schmidt-Böcking
authors.forename: Hartmut G
authors.initials: HG
authors.lastname: Roskos
authors.forename: Reinhard
authors.initials: R
authors.lastname: Dörner
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D053844:Lasers, Solid-State; D009556:Niobium / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D055053:Terahertz Radiation
chemical_list: D010087:Oxides; D009556:Niobium; C091692:lithium niobate