Extending the Thermal Near Field Through Compensation in Hyperbolic Waveguides

Abstract

A promising method to leverage near-field power densities without the use of nanoscale vacuum gaps is through hyperbolic metamaterial (HMM) waveguides. When placed between a hot and cold reservoir, an ideal HMM can transmit surface waves across several microns, enabling an extension of near-field enhancements. However, when accounting for transmission loss due to realistic levels of absorption within the waveguide, previous studies have shown that the enhancements are significantly curtailed at wide separations. In our study, we investigate the role of internal sources within realistic non-isothermal HMMs. We demonstrate that, in some cases, the emission from the HMM accounts for over 90% of the total heat transfer to the receiver, and that these additional sources can largely compensate for optical losses associated with decreased transmission from the emitter to the receiver. Lastly, we investigate the spectral transport in a realistic 3-body system which has mismatching optical properties between the boundaries (emitter and receiver) and the waveguide (HMM). Our model shows that the near-field thermal transport remains spectrally selective to the boundaries, even as major radiative contributions come from the waveguide. This work may enable the design of non-isothermal emitter-waveguide-receiver systems that transmit near-field power levels over wider separations.

Performance improvement of three-body radiative diodes driven by graphene surface plasmon polaritons

“…To overcome this limitation, we seek a solution from the emerging theory of three-body NFRHT, which exhibits more abundant and novel physical phenomena compared to the classic two-body system, 28 due to the complexity of the heat transfer mechanism. [29][30][31] Messina and Antezza derived an expression for the near-field radiative heat flux of a three-body system in a thermal environment. 32 Based on this theory, an amplifier for photon heat tunneling was found based on a passive relay system.…”

Enhancement and Manipulation of Near-Field Thermal Radiation Using Hybrid Hyperbolic Polaritons

“…Since the hybrid effect can optimize the optical performance of the system, continuous efforts have been devoted to exploring the influence of the hybridization between polaritons on heat transfer. − Typically, one valuable strategy relies on the hybrid effect between the isotropic SPPs and the hyperbolic modes of the uniaxial hyperbolic substrate. Approaches based on this idea have produced remarkable research progress in improving NFRHT. − For instance, Liu et al found a perfect photon tunneling with near-unity probability across the broad frequency and k -space region on the basis of the hybridization of graphene plasmons and hyperbolic modes. However, fundamental studies for the hybrid effect of the uniaxial hyperbolic substrate on anisotropic surface polaritons have so far remained elusive, especially in the field of thermal radiation.…”