Nonreciprocity in transmission mode with planar structures for arbitrarily polarized light [Invited]

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.