Theory of thermal radiation of non-Hermitian photonic crystals

We present a theoretical study of thermal radiation of non-Hermitian photonic crystals. We found that lossless photonic crystals can have exceptional points in reciprocal spaces. Such exceptional points manifest sharp crossings in the reflection and transmission spectrums. We develop a scattering matrix formulation to analyze such properties. We calculate and simulate thermal radiation of such a photonic crystal using the methods of fluctuational electrodynamics. Thermal radiation of such a system shows anomalous emission spectrums related to near-filed to far-field couplings.