Sub-50 fs pulses at 2050 nm from a picosecond Ho:YLF laser using a two-stage Kagome-fiber-based compressor

The high-energy few-cycle mid-infrared laser pulse beyond 2 μm is of immense importance for attosecond science and strong-field physics. However, the limited gain bandwidth crystals such as Ho:YLF Ho:YAG allows generation picosecond (ps) long pulses and, hence, makes it challenging to generate at without utilizing an optical parametric chirped-pulse amplifier (OPCPA). Moreover, exclusive use near-infrared wavelength has wavelengths 4 Furthermore, high harmonic (HHG) conversion efficiency reduces dramatically when driven by a long-wavelength laser. Novel schemes multi-color HHG have been proposed enhance flux. Therefore, highly desirable femtosecond from driving these experiments. Here, we utilize two-stage nonlinear spectral broadening compression based on Kagome-type hollow-core photonic crystal fiber (HC-PCF) compress few-ps sub-50 fs 1 kHz repetition rate. We demonstrate both experimentally numerically 3.3 ps 140 μJ 48 11 with focal intensity reaching 10 13 W / cm 2 . Thereby, this system can be used in solids μm. In first stage, are spectrally broadened Kagome compressed silicon-based prism compressor 285 energy 90 μJ. second self-compressed air-filled HC-PCF. With fine-tuning group delay dispersion (GDD) externally 3 mm window, achieved. This leads 70-fold 2050 nm. further white light focusing into thin medium YAG.