Finite-size corrections to the radiation laws of a Kerr nonlinear blackbody

In a Kerr nonlinear blackbody (KNB), bare photons with opposite wave vectors and helicities are bound into pairs and unpaired photons are transformed into nonpolaritons. The nonpolariton system can constitute free thermal radiation in the blackbody. The present paper investigates the radiation of a KNB in a cavity of finite-size. For a given geometry, we obtain explicit expressions of the modified Planck and Stefan–Boltzmann blackbody radiation laws as a function of the temperature, size and shape of the cavity by using semiclassical techniques. Moreover, we discuss these corrections of a spherical KNB and the range of parameters (temperature and size of the cavity) in which these effects are accessible to experimental detection. Finally, we calculate the finite-size corrections (FSCs) under these conditions, and this work may lay the foundation for the experimental verification of a KNB.