Article

Applied Physics B

, Volume 74, Supplement 1, pp s237-s243

First online:

Sub-6-fs blue pulses generated by quasi-phase-matching second-harmonic generation pulse compression

  • L. GallmannAffiliated withUltrafast Laser Physics Laboratory, Institute of Quantum Electronics, Swiss Federal Institute of Technology, ETH Hönggerberg – HPT, 8093 Zürich, Switzerland
  • , G. SteinmeyerAffiliated withUltrafast Laser Physics Laboratory, Institute of Quantum Electronics, Swiss Federal Institute of Technology, ETH Hönggerberg – HPT, 8093 Zürich, Switzerland
  • , G. ImeshevAffiliated withE.L. Ginzton Laboratory, Stanford University, Stanford, CA 94305, USA
  • , J.-P. MeynAffiliated withFachbereich Physik, Universität Kaiserslautern, 67663 Kaiserslautern, Germany
  • , M.M. FejerAffiliated withE.L. Ginzton Laboratory, Stanford University, Stanford, CA 94305, USA
  • , U. KellerAffiliated withUltrafast Laser Physics Laboratory, Institute of Quantum Electronics, Swiss Federal Institute of Technology, ETH Hönggerberg – HPT, 8093 Zürich, Switzerland

Abstract.

We demonstrate a novel scalable and engineerable approach for the frequency-doubling of ultrashort pulses. Our technique is based on quasi-phase-matching and simultaneously provides tailored dispersion and nonlinear frequency conversion of few-cycle optical pulses. The method makes use of the spatial localization of the conversion process and the group velocity mismatch in a chirped grating structure. The total group delay of the nonlinear device can be designed to generate nearly arbitrarily chirped second-harmonic pulses from positively or negatively chirped input pulses. In particular, compressed second-harmonic pulses can be obtained. A brief summary of the underlying theory is presented, followed by a detailed discussion of our experimental results. We experimentally demonstrate quasi-phase-matching pulse compression in the sub-10-fs regime by generating few-cycle pulses in the blue to near-ultraviolet spectral range. Using this new frequency conversion technique, we generate sub-6-fs pulses centered at 405 nm by second-harmonic generation from a 8.6 fs Ti:sapphire laser pulse. The generated spectrum spans a bandwidth of 220 THz. To our knowledge, these are the shortest pulses ever obtained by second-harmonic generation.

PACS: 42.65.Ky; 42.65.Re; 42.79.Nv