  This paper presents an in-band Full Duplex (FD) integrated sensing and
communications system comprising a holographic Multiple-Input Multiple-Output
(MIMO) base station, which is capable to simultaneously communicate with
multiple users in the downlink direction, while sensing targets being randomly
distributed within its coverage area. Considering near-field wireless operation
at THz frequencies, the FD node adopts dynamic metasurface antenna panels for
both transmission and reception, which consist of massive numbers of
sub-wavelength-spaced metamaterials, enabling reduced cost and power
consumption analog precoding and combining. We devise an optimization framework
for the FD node's reconfigurable parameters with the dual objective of
maximizing the targets' parameters estimation accuracy and the downlink
communication performance. Our simulation results verify the integrated sensing
and communications capability of the proposed FD holographic MIMO system,
showcasing the interplays among its various design parameters.
