Single-stage GaSe OPCPA delivering high-energy few-cycle pulses at 11 µm wavelength – INVITEDMartin Bock, Dennis Ueberschaer, Pia Fuertjes and Uwe GriebnerEPJ Web Conf., 287 (2023) 08002DOI: https://doi.org/10.1051/epjconf/202328708002