  We introduce the new concept of "metalines" for manipulating the amplitude
and phase profile of an incident wave locally and independently. Thanks to the
highly confined graphene plasmons, a transmit-array of graphene-based metalines
is used to realize analog computing on an ultra-compact, integrable and planar
platform. By employing the general concepts of spatial Fourier transformation,
a well-designed structure of such meta-transmit-array combined with graded
index lenses can perform two mathematical operations; i.e. differentiation and
integration, with high efficiency. The presented configuration is about 60
times shorter than the recent structure proposed by Silva et al.(Science, 2014,
343, 160-163); moreover, our simulated output responses are in more agreement
with the desired analytic results. These findings may lead to remarkable
achievements in light-based plasmonic signal processors at nanoscale instead of
their bulky conventional dielectric lens-based counterparts.
