Achromatic dual-waveplate for inline two color high-order harmonic generation Neven Ibrakovic, Esben Witting Larsen, Götz Zinner and Johan Mauritsson Eur. Phys. J. D, 72 9 (2018) 148 Published online: 07 September 2018 DOI: 10.1140/epjd/e2018-80759-9