Quantum nonlinear mixing of thermal photons to surpass the blackbody limit
Abstract
Nearly all thermal radiation phenomena involving materials with linear response can be accurately described via semiclassical theories of light. Here, we go beyond these traditional paradigms to study a nonlinear system which, as we show, necessarily requires quantum theory of damping. Specifically, we analyze thermal radiation from a resonant system containing a $\chi^{(2)}$ nonlinear medium and supporting resonances at frequencies $\omega_1$ and $\omega_2\approx 2\omega_1$, where both resonators are driven only by intrinsic thermal fluctuations. Within our quantum formalism, we reveal new possibilities for shaping the thermal radiation. We show that the resonantly enhanced nonlinear interaction allows frequencyselective enhancement of thermal emission through upconversion, surpassing the wellknown blackbody limits associated with linear media. Surprisingly, we also find that the emitted thermal light exhibits nontrivial statistics ($g^{(2)}(0) \neq 2$) and biphoton intensity correlations (at two distinct frequencies). We highlight that these features can be observed in the near future by heating a properly designed nonlinear system, without the need for any external signal. Our work motivates new interdisciplinary inquiries combining the fields of nonlinear photonics, quantum optics and thermal science.
 Publication:

Optics Express
 Pub Date:
 January 2020
 DOI:
 10.1364/OE.377278
 arXiv:
 arXiv:1910.00113
 Bibcode:
 2020OExpr..28.2045K
 Keywords:

 Physics  Optics;
 Condensed Matter  Mesoscale and Nanoscale Physics;
 Physics  Applied Physics;
 Quantum Physics
 EPrint:
 doi:10.1364/OE.377278