  HARMONI is a visible and near-infrared integral field spectrograph equipped
with two complementary adaptive optics systems, fully integrated within the
instrument. A Single Conjugate AO (SCAO) system offers high performance for a
limited sky coverage and a Laser Tomographic AO (LTAO) system provides AO
correction with a very high sky-coverage. While the deformable mirror
performing real-time correction of the atmospheric disturbances is located
within the telescope itself, the instrument contains a suite of
state-of-the-art and innovative wavefront sensor systems. Laser guide star
sensors (LGSS) are located at the entrance of the instrument and fed by a
dichroic beam splitter, while the various natural guide star sensors for LTAO
and SCAO are located close to the science focal plane. We present
opto-mechanical architecture and design at PDR level for these wavefront sensor
systems.
