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.
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Received: 17 September 2001 / Revised version: 27 November 2001 / Published online: 27 June 2002
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Gallmann, L., Steinmeyer, G., Imeshev, G. et al. Sub-6-fs blue pulses generated by quasi-phase-matching second-harmonic generation pulse compression. Appl Phys B 74 (Suppl 1), s237–s243 (2002). https://doi.org/10.1007/s00340-002-0886-8
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DOI: https://doi.org/10.1007/s00340-002-0886-8