Thermal radiation of Er doped dielectric crystals: Probing the range of applicability of the Kirchhoff law

Ekembu K. Tanyi, Brandi T. Burton, Evgenii E. Narimanov +1

The Kirchhoff law of thermal radiation, relating emissivity ε and absorptance α, has been originally formulated for opaque bodies in thermodynamic equilibrium with the environment.…