System-level block diagram of LBTI architecture in nulling mode showing the optical path through the telescope, beam combiner (red box), and the NIC cryostat (blue box). After being reflected on LBT primaries, secondaries, and tertiaries, the visible light is reflected on the entrance window and used for wavefront sensing while the infrared light is transmitted into LBTI, where all subsequent optics are cryogenic. The beam combiner directs the light with steerable mirrors and can adjust pathlength for interferometry. Inside the NIC cryostat, the thermal near-infrared (3–5 μm) light is directed to LMIRCam for exoplanet imaging, the near-infrared (1.5–2.5 μm) light is directed to the phase sensor, which measures the differential tip/tilt and phase between the two primary mirrors, and the mid-infrared (8–13 μm) light is directed to NOMIC for nulling interferometry. Both outputs of the beam combiner are directed to the phase and tip/tilt sensor, while only the nulled output of the interferometer is reflected to the NOMIC camera with a short-pass dichroic. The various cameras are shown in dark gray, and feedback signals driving the deformable secondary mirrors and tip-tilt/OPD correctors are represented by dashed lines. Note that this diagram is schematic only and does not show several additional optics.