Open AccessFemtosecond 85 μm source based on intrapulse difference-frequency generation of 21 μm pulses
Author(s) -
Ondřej Novák,
Peter Krogen,
Tobias Kroh,
Tomáš Mocek,
Franz X. Kärtner,
Kyung-Han Hong
Publication year - 2018
Publication title -
optics letters/optics index
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.524
H-Index - 272
eISSN - 1071-2763
pISSN - 0146-9592
DOI - 10.1364/ol.43.001335
Subject(s) - optics , femtosecond , ultrafast optics , pulse shaping , materials science , sum frequency generation , physics , nonlinear optics , laser
We report on a femtosecond ∼8.5 μm, ∼2 μJ source based on the intrapulse difference-frequency generation (DFG) of 2.1 μm pulses in an AgGaSe 2 (AGSe) crystal. Compared to the conventional ∼0.8 or 1 μm near-infrared (IR) pulses, a ∼2 μm driver for intrapulse DFG can provide more efficient conversion into the wavelengths longer than 5 μm due to a lower quantum defect and is more suitable for the non-oxide nonlinear crystals that have a relatively low bandgap energy. Using 26 fs, 2.1 μm pulses for type-II intrapulse DFG, we have generated intrinsically carrier-envelope phase-stable idler pulses with a conversion efficiency of 0.8%, which covers the wavelength range of 7-11 μm. Our simulation study shows that the blueshift of intrapulse DFG is assisted by self-phase modulation of the driving pulses in AGSe. The idler pulses are particularly useful for strong-field experiments in nanostructures, as well as for seeding parametric amplifiers in the long-wavelength IR.