Strong broadband terahertz (THz) radiation sources are in high demand in THz spectroscopy and THz-field matter interactions. The widely studied two-color laser scheme  can provide such THz sources with field strengths up to multi MV/cm . In this scheme, the frequency ratio of the two laser pulses is fixed at ω2/ω1 =1:2. Recently, whether this scheme can be extended to other frequency ratios has become a hot issue [3-5]. Among them, our two theoretic reports [3,5] have predicted that THz radiation can still be generated with some new frequency ratios ω2/ω1 =1:4, 2:3, etc.
© 2018 The Author(s)PDF Article