  Measuring the diffuse, highly-ionized baryonic content in galactic halos and
the intergalactic medium through soft x-ray absorption spectroscopy of active
galactic nuclei is a main scientific objective of the Lynx X-ray Observatory
mission concept that can only be accomplished with a next-generation grating
spectrometer. Realizing such an instrument using reflection grating technology
requires thousands of custom blazed gratings that each perform with high
diffraction efficiency to be manufactured and aligned to intercept radiation
coming to a focus in a Wolter-I telescope. The aim of this thesis is to
implement two recently-developed techniques in nanofabrication for this task,
with an emphasis on beamline diffraction-efficiency testing for characterizing
spectral sensitivity. In particular, thermally-activated selective topography
equilibration (TASTE) is pursued as a means for fabricating a master grating
with the key advantage that it enables blazed groove facets to be patterned in
polymeric electron-beam resist over a non-parallel groove layout not limited by
substrate crystal structure. Additionally, substrate-conformal imprint
lithography (SCIL) is studied as a method for mass manufacturing high-fidelity
grating replicas in a silica sol-gel resist while avoiding many of the
detriments associated with large-area patterning in other nanoimprint
techniques. Diffraction-efficiency testing of sub-micron grating prototypes
coated with gold shows that TASTE is capable of meeting Lynx requirements for
spectral sensitivity, with room for improvement at small groove periods, and
that while SCIL offers a promising avenue for Lynx grating production, imprints
suffer a small blaze-angle reduction due to resist shrinkage. Accompanying this
dissertation are appendices that outline physics fundamentals for x-ray
spectral lines, x-ray optics, and diffraction gratings.
