  Approaching thermodynamic limits in light harvesting requires enabling
nonreciprocal thermal emission. The majority of previously reported
nonreciprocal thermal emitters operate in reflection mode, following original
proposals by M. Green and others. In these proposals, cascaded nonreciprocal
junctions that re-direct each junction's emission towards a subsequent one are
employed for efficient light-harvesting. Recently, simplified concepts have
been proposed in solar photovoltaics and thermophotovoltaics that leverage the
concept of tandem junctions to approach thermodynamic limits. In these
simplified scenarios, polarization-independent nonreciprocal response in
transmission mode is required. We propose a pattern-free heterostructure that
enables such functionality, using a magneto-optical material embedded between
two dissimilar dielectric layers.
