Nonreciprocity in transmission mode with planar structures for arbitrarily polarized light

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 [ Nano Lett. 12 , 5985 ( 2012 ) 10.1021/nl3034784 ] 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, respectively, 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.