  Color tuning is a fascinating and indispensable property in applications such
as advanced display, active camouflaging and information encryption. Thus far,
a variety of reconfigurable approaches have been implemented to achieve color
change. However, it is still a challenge to enable a continuous color tuning
over the entire hue range in a simple, stable and rapid manner without changes
in configuration and material properties. Here, we demonstrate an all-optical
continuously tunable plasmonic pixel scheme via a modular design approach to
realize polarization-controlled full color tuning by breaking the intrinsic
symmetry of the unit cell layout. The polarization-controlled full color
tunable plasmonic pixels consist of three different types of color modules
oriented at an angle of 60{\deg} with respect to each other, corresponding to
three subtractive primary colors. Without changing the structural properties or
surrounding environment, the structural colors can be continuously and
precisely tuned across all hues by illuminating linearly polarized light with
different polarization directions. Meanwhile, the plasmonic pixels can be
flexibly customized for various color tuning processes, such as different
initial output colors and color tuning sequences, through the appropriate
choice of component modules and the elaborate design of module layouts.
Furthermore, we extend the color tuning to achromatic colors, white or black,
with the utilization of a single module or the introduction of a black module.
The proposed polarization-controlled full color tunable plasmonic pixels hold
considerable potential to function as next-generation color pixels integrated
with liquid-crystal polarizers.
