Nonreciprocal scintillation using magneto-optical photonic crystals

Scintillation describes the conversion of high-energy particles into light in transparent media and finds diverse applications such as high-energy particle detection and industrial and medical imaging. This process operates on multiple timescales, with the final radiative step consisting of spontaneous emission, which can be modeled within the framework of fluctuational electrodynamics. Scintillation can therefore be controlled and enhanced via nanophotonic effects, which has been experimentally demonstrated in recent works. Such designs have thus far obeyed Lorentz reciprocity, meaning there is a direct equivalence between scintillation emission from the design and absorption of a plane wave in the far-field. However, scintillators that do not obey reciprocity have not been explored, even though they represent a novel platform for probing emission which is both nonequilibrium and nonreciprocal in nature. In this work, we propose to harness nonreciprocity to achieve directional control of scintillation emission, granting an additional degree of control over scintillation. Such directionality of light output is important in improving collection efficiencies along off-normal directions towards detectors in certain radiation detection schemes. We present the design of a nonreciprocal scintillator using a one-dimensional magnetophotonic crystal in the Voigt configuration. Our work demonstrates the potential of controlling nonequilibrium emission such as scintillation by breaking reciprocity and expands the space of nanophotonic design for achieving such control.