  Polarized light has various potential applications in the communication
bands, including optical communication, polarization imaging, quantum emission,
and quantum communication. However, optimizing polarization control requires
continuous improvements in areas such as dynamic tunability, materials, and
efficiency. In this work, we propose a borophene-based structure capable of
converting linearly polarized light into arbitrarily polarized light through
the coherent excitation of localized surface plasmons (LSPs) in optical
communication band. Furthermore, a double-layer borophene structure can be
achieved by placing a second borophene array at the top of the first one with a
90{\deg} relative rotation of their crystalline plane. The rotation direction
of the polarization state of the reflected light can be switched by
independently controlling the carrier concentration of the two-layer borophene.
Finally, a dipole source is used to realize the emission of polarized light,
which is two orders of magnitude higher than the emission rate in free space,
and the polarization state can be dynamically controlled by manipulating the
carrier concentration. Our study is simple and compact, with potential
applications in the fields of polarizers, polarization detectors, and quantum
emitters.
