Wavelength and phase considerations for multi-pulse plasma generation of terahertz

We present a numerical study on plasma generation of THz radiation utilizing multiple light pulses of various wavelengths in an optical scheme that is readily achievable in a tabletop environment. To achieve coherent THz emission it is necessary to carefully consider all the wavelengths involved in a multi-pulse setup. Previous theoretical work has explored ideal waveforms and electric field symmetries for optimal efficiency in generating THz from plasma [Phys. Rev. Lett. 114 183901 (2015)]. In practice such setups are quite delicate and prone to instability. We show that wavelength combinations with lower theoretical efficiency can more easily produce stable THz pulses in a tabletop environment combining readily available near-infrared wavelengths.