We report progress in the design, theoretical modeling and experimental characterisation of microchannel plate
(MCP) X-ray optics for the BepiColombo Mercury Imaging X-ray Spectrometer (MIXS). We show that MCP
optics technology allows the design of a highly capable imaging telescope with 1 m focal length, a 1° field of
view and approximately 50 cm<sup>2</sup> of on-axis effective area at 1 keV. Of a total instrument mass budget 7.3 kg, less
than 2.3 kg is allocated to the optics assemblies, telescope tubes, support structures and the electron diverters
(used to deflect electrons from the focal plane). The instrument science goals require an imaging resolution of 9
arcminutes, with a design goal of 2 arcminutes. Recent experimental data, taken from individual optic elements
is presented to show that MCP quality is in good agreement with the error budgets assumed in theoretical
calculations of performance.
Design and manufacturing of diffractive optical elements (DOEs) are presented. Mass replication methods for DOEs are explained including UV-replication, micro-injection moulding and reel-to-reel production. Novel applications of diffractive optics including spectroscopic surface relief gratings, antireflection surfaces, infrared light rejection gratings, light incoupling into thin waveguides, and additive diffractive colour mixing are presented.