  Terahertz (THz) detector has great potential for use in imaging,
spectroscopy, and communications due to its fascinating interactions between
radiation and matter. However, current THz detection devices have limitations
in sensitivity, operating frequency range, and bulky footprint. While recent
ferroelectric-integrated graphene plasmonic devices show promise in overcoming
these limitations, they are not yet extended to the THz range. Here, we propose
a wavelength-sensitive terahertz detector that uses a single layer graphene
integrated onto the ferroelectric thin film with patterned polarization
domains. This device works at room temperature, with high responsivity and
detectivity by coupling graphene plasmons with THz frequencies through spatial
modulation of carrier behaviors using ferroelectric polarization, without
requiring additional local electrodes. By reconfiguring an interweaving squared
ferroelectric domain array with alternating upward and downward polarizations
to highly confine graphene surface plasmon polaritons, our device achieves an
ultrahigh responsivity of 1717 A W-1 and a normalized detectivity of 1.07*10^13
Jones at a resonance frequency of 6.30 THz and a 0.3 V bias voltage. We also
show that the device makes possible for spectrum reconstruction application of
portable spectrometer combining the mathematical algorithms.
