  Although tremendous achievements have been made toward inertial confinement
fusion, laser plasma instabilities (LPIs) remain to be an inevitable problem
for current drive schemes. To mitigate these instabilities, significant efforts
have been paid to produce high-power broadband ultraviolet lasers. However, no
practical scheme has been demonstrated up to now for efficient triple-frequency
conversion of broadband laser. Here we propose the design of polychromatic
drivers for the generation of multicolor beams mainly based upon the optical
parametric amplification, which can significantly enhance the third-harmonic
conversion efficiency. Each polychromatic light has four colors of
monochromatic beamlets with a full spectrum width of 3\%, and the beamlet
colors of any two adjacent flanges are different. The suppression effects of
such polychromatic lights have been investigated via large scale
particle-in-cell simulations, which indicate that more than 35\% of the
incident energy can be saved from the LPIs compared with monochromatic lasers
for the direct-drive scheme, or high-density filled target for the
indirect-drive scheme. The proposed polychromatic drivers are based on the
matured technologies, and thus may pave the way towards realization of robust
and high-efficiency fusion ignition.
