  The Zero Contrast Grating (ZCG) is a promising candidate for moded and
dispersive mid-infrared (MIR) photonics for its broadband transmittance and
reflectance greater than 99.9%. The optimal grating design including refractive
index and grating parameters is investigated, and is compared to its analogue
the High Contrast Grating (HCG). This study provides insights on how ZCG can
manipulate the electromagnetic waves within the low refractive index dielectric
bars. The foundations following its near-perfect transmittance and reflectance
due to phase matching are described from the perspective of diffraction orders
and dispersion relations. Both 0th and 1st order diffraction contribute to
construction or destruction of interferences that occur at the output plane,
which is a significant finding in differentiating ZCG and HCG. Applications for
the ZCG can be found in selective bandpass windows, beam splitters, broadband
reflectors, and narrowband thermal emitters.
