Polarization oscillations of near-field thermal emission

TL;DR

This paper investigates how the polarization of near-field thermal emission oscillates spatially at thermal equilibrium, revealing oscillations with a period of about half the optical wavelength across various materials.

Contribution

It demonstrates that the degree of polarization exhibits spatial oscillations at thermal equilibrium, contrasting previous findings of monotonic decay, and applies to diverse dielectric and metallic systems.

Findings

Polarization exhibits spatial oscillations at thermal equilibrium.

Oscillation period is approximately half the optical wavelength.

Contrasts with previous monotonic decay results.

Abstract

We consider the polarization of thermal emission in the near-field of various materials including dielectrics and metallic systems with resonant surface modes. We find that at thermal equilibrium, the degree of polarization exhibits spatial oscillations with a period of approximately half the optical wavelength, independent of material composition. This result contrasts with that of Setala, Kaivola and Friberg [Phys. Rev. Lett. 88, 123902 (2002)], who find monotonic decay of the degree of polarization for systems in local thermal equilibrium.