We present progress in the development of the monolithic achromatic nulling interference coronagraph (MANIC),
an optic designed for enabling direct detection and characterization of exoplanetary systems around nearby stars.
MANIC is a fully symmetric implementation of a rotational shearing interferometer consisting of fused quartz
prisms and a symmetric beamsplitter optically contacted in an arrangement that geometrically flips the fields
in the TR and RT arms about orthogonal axes such that upon recombination, a centro-symmetric, theoretically
achromatic null is produced. In addition to a small inner working angle (⪅ 1λ/D), built-in alignment and
stability are inherent benefits of the compact monolithic design, which make MANIC a competitive alternative
to conventional discrete element nullers proposed for imaging exoplanetary environments. Following MANIC's
initial fabrication, the path error between its TR and RT arms was measured. This measurement was used to
fabricate compensator plates of varying thicknesses that were bonded to the optic to reduce dispersion imbalance,
thereby improving broadband nulling performance. In performing this correction, initial OPD was reduced from
949 ± 44 nm to 63 ± 10 nm, which in the absence of any other asymmetries, corresponds to an increase in a
107 R-band (λc = 648 nm) nulling bandpass from monochromatic to 25%, or at the 106 level, from 5% to 50%.
Current benchtop laser and polychromatic nulling strategies are described. The potential science return from
using MANIC on a sub-orbital platform is discussed.