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- ItemGeneration of millijoule few-cycle pulses at 5 Ī¼m by indirect spectral shaping of the idler in an optical parametric chirped pulse amplifier(Washington, DC : Soc., 2018) Bock, Martin; Grafenstein, Lorenz von; Griebner, Uwe; Elsaesser, ThomasSpectral pulse shaping in a high-intensity midwave-infrared (MWIR) optical parametric chirped pulse amplifier (OPCPA) operating at 1 kHz repetition rate is reported. We successfully apply a MWIR spatial light modulator (SLM) for the generation of ultrashort idler pulses at 5 Ī¼m wavelength. Only bulk optics and active phase control of the 3.5 Ī¼m signal pulses via the SLM are employed for generating compressed idler pulses with a duration of 80 fs. The 80-fs pulse duration corresponds to less than five optical cycles at the central wavelength of 5.0 Ī¼m. The pulse energy amounts to 1.0 mJ, which translates into a peak power of 10 GW. The generated pulse parameters represent record values for high-intensity MWIR OPCPAs.
- ItemMulti-millijoule, few-cycle 5āĀµm OPCPA at 1ākHz repetition rate(Washington, DC : Soc., 2020) von Grafenstein, Lorenz; Bock, Martin; Ueberschaer, Dennis; Escoto, Esmerando; KoƧ, Azize; Zawilski, Kevin; Schunemann, Peter; Griebner, Uwe; Elsaesser, ThomasA table-top midwave-infrared optical parametric chirped pulse amplification (OPCPA) system generates few-cycle pulses with multi-10 GW peak power at a 1 kHz repetition rate. The all-optically synchronized system utilizes ZnGeP2 nonlinear crystals and a highly stable 2 Āµm picosecond pump laser based on Ho:YLiF4. An excellent energy extraction is achieved by reusing the pump pulse after the third parametric power amplification stage, resulting in 3.4 mJ idler pulses at a center wavelength of 4.9 Āµm. Pulses as short as 89.4 fs are achieved, close to only five optical cycles. Taking into account the pulse energy, a record high peak power of 33 GW for high-energy mid-IR OPCPAs beyond 4 Āµm wavelength is demonstrated. Ā© 2020 OSA - The Optical Society. All rights reserved.
- ItemSpatial distribution of electric-field enhancement across the gap of terahertz bow-tie antennas(Washington, DC : Soc., 2020) Runge, Matthias; Engel, Dieter; Schneider, Michael; Reimann, Klaus; Woerner, Michael; Elsaesser, ThomasThe electric-field enhancement in terahertz (THz) antennas designed for nonlinear THz spectroscopy of soft matter is characterized by spatially resolved electrooptic sampling. To mimic the relevant interaction geometry, metallic, resonant bow-tie antennas are deposited on a thin zinc telluride crystal of 10 Āµm thickness. The THz electric field transmitted through the antenna gap is recorded by electrooptic sampling. By focusing the 800 nm, sub-20 fs sampling pulses, we achieve a spatial resolution of some 3 Āµm, which is 1/3 to 1/8 of the antenna-gap width. The THz field in the gap displays an enhancement by a factor of up to 4.5 with a pronounced spectral variation, depending sensitively on the antenna-arm length and the gap width. By scanning the 800 nm probe spot laterally through the antenna gap, the spatial variation of the enhancement is determined, reaching the highest values at the edges of the gap. The results are in agreement with simulations of the electric-field distributions by finite-element calculations. Ā© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement