  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.
