Multi-mJ mid-infrared kHz OPCPA and Yb-doped pump lasers for tabletop coherent soft x-ray generation. (September 2015)

• Record Type: Journal Article
• Authors: Lai, Chien-Jen; Hong, Kyung-Han; Siqueira, Jonathas P; Krogen, Peter; Chang, Chun-Lin; Stein, Gregory J; Liang, Houkun; Keathley, Phillip D; Laurent, Guillaume; Moses, Jeffrey; Zapata, Luis E; Kärtner, Franz X
• Is Part Of: Journal of optics. Volume 17:Number 9(2015:Sep.)
• Page Start: 5383
• Publication Date: 2015-09
• Subjects: Optics -- Periodicals; 535.05
• DOI: 10.1088/2040-8978/17/9/094009
• Languages: English
• ISSNs: 2040-8978

Abstract

<abstract> <title>Abstract</title> <p>We present our recent progress on the development of a mid-infrared (mid-IR), multi-mJ, kHz optical parametric chirped-pulse amplification (OPCPA) system, pumped by a homebuilt picosecond cryogenic Yb:YAG chirped-pulse amplifier, and its application to soft x-ray high-order harmonic generation. The cryogenic Yb:YAG laser operating at 1 kHz repetition rate delivers 42 mJ, 17 ps, 1.03 <italic>μ</italic>m pulses to pump the OPCPA system. Efficient second and fourth harmonic generations from the Yb:YAG system are demonstrated, which provide the pumping capability for OPCPA at various wavelengths. The mid-IR OPCPA system produces 2.6 mJ, 39 fs, 2.1 <italic>μ</italic>m pulses with good beam quality (<italic>M</italic>² = ∼1.5) at 1 kHz repetition rate. The output pulses of the OPCPA are used to generate high-order harmonics in both gas cell and hollow-core fiber targets. A photon flux of ∼2 × 10⁸ photon/s/1% bandwidth at 160 eV in Ar is measured while the cutoff is 190 eV. The direct measurements of the photon flux from x-ray photodiodes have confirmed the generation of water-window soft x-ray photons with a flux ∼10⁶ photon/s/1% bandwidth at 330 eV in Ne. The demonstrated OPCPA and Yb:YAG pump laser technologies provide an excellent platform of energy and power scalable few-cycle mid-IR sources that are suitable for high-flux tabletop coherent soft x-ray generation.</p> </abstract>