CC BY
12LS-I-4
Millijoule level, sub 8 cycle, 7 ^m OPCPA on a tabletop: design, applications and routes for future development.
L. Maidment1, U. Elu1, D. Sánchez1, T. Steinle1, K. Zawilski2, P. Schunemann2, G. Matras3, C. Simon-Boisson3, J. Biegert1,4
1ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels- Barcelona, Spain
2BAESystems, MER15-1813-P.O. Box 868, Nashua-New Hampshire 03061, USA 3THALES Optronique S.A.S, Laser Solutions Unit- 2 avenue Gay-Lussac, 78995 Elancourt Cedex, France
4ICREA, Pg. Lluis Companys 23, 08010 Barcelona, Spain
Carrier-to-envelope phase (CEP) stable ultrashort and intense mid-infrared pulses promise applications such as multi-kilo-electron-volt coherent X-ray generation [1] and the study of strong field physics [2]. However, above 5-^m wavelength it has typically been challenging to generate intense few cycle pulses as no practical laser materials with sufficient gain bandwidth exist and most commonly used nonlinear materials are opaque [3].
We present the development of a 7 |im optical parametric chirped pulse amplifier (OPCPA) based on zinc germanium phosphide. Pulses at 100 Hz with 0.70-mJ energy and 188-fs duration after compression (8 optical cycles) are produced. An intermediate chirp inversion stage is used to permit pulse compression with 93.5% efficiency in bulk BaF2. Additionally, the 7 |im seed to the OPCPA is generated though difference frequency generation between two beams from the same source, making the mid-infrared beam passively CEP stable.
As an application demonstration, the output is used to generate high harmonics in ZnSe spanning the near infrared into the visible spectral region, reaching harmonic order 13. We also present plans for energy scaling of the system. The high intensity, passively CEP stable mid-infrared pulses make this table-top source a key enabling tool for strong field physics and keV-level coherent x-ray sources.
References
[1] T. Popmintchev et al., "Bright coherent ultrahigh harmonics in the kev x-ray regime from mid-infrared femtosecond lasers," Science 336(6086), 1287-1291 (2012).
[2] B. Wolter et al., "Strong-field physics with Mid-IR fields," Phys. Rev. X 5(2), 1-16 (2015).
[3] V. Petrov, "Frequency down-conversion of solid-state laser sources to the mid-infrared spectral range using non-oxide nonlinear crystals," Prog. Quantum Electron. 42, 1-106 (2015).
