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Abstract A mathematical model has been developed to study far-field and near-field thermal emission from non-continuous periodic structures. Non-continuous periodic structures with appropriate geometries and materials can support electric or magnetic resonance, idealized for designing far-field perfect absorbers and near-field emitters/absorbers supporting long-distance photon tunneling. However, these structures do not have close format dyadic Green’s function to describe the thermal radiation from randomly fluctuating thermal current. Thus, simulating the near-field radiation spectrum between emitters and collectors patterned with these non-continuous periodic structures is challenging. Though finding eigenmodes of white-noise-like fluctuating thermal current satisfying this specific geometry, we extended the Wiener-Chaotic expansion type of near-field simulation to study far-field and near-field thermal emission from non-continuous periodic structures. After verifications with reference cases, the new mathematical method is applied to study photon tunneling between the emitter and the collector patterned with single-ring split ring resonance rings (SRR) supporting magnetic field resonance. It is observed from the new mathematical model that long photon tunneling can occur under such a configuration through magnetic field coupling between the emitter and collector at the magnetic resonance frequency of SRRs.
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Quantum torque on a non-reciprocal body out of thermal equilibrium and induced by a magnetic field of arbitrary strength
Abstract A stationary body that is out of thermal equilibrium with its environment, and for which the electric susceptibility is non-reciprocal, experiences a quantum torque. This arises from the spatially non-symmetric electrical response of the body to its interaction with the non-equilibrium thermal fluctuations of the electromagnetic field: the non-equilibrium nature of the thermal field fluctuations results in a net energy flow through the body, and the spatially non-symmetric nature of the electrical response of the body to its interaction with these field fluctuations causes that energy flow to be transformed into a rotational motion. We establish an exact, closed-form, analytical expression for this torque in the case that the environment is the vacuum and the material of the body is described by a damped oscillator model, where the non-reciprocal nature of the electric susceptibility is induced by an external magnetic field, as for magneto-optical media. We also generalise this expression to the context in which the body is slowly rotating. By exploring the high-temperature expansion of the torque, we are able to identify the separate contributions from the continuous spectral distribution of the non-reciprocal electric susceptibility, and from the resonance modes. In particular, we find that the torque persists in the limiting case of zero damping parameter, due to the contribution of the resonance modes. We also consider the low-temperature expansion of the torque. This work extends our previous consideration of this model to an external magnetic field of arbitrary strength, thereby including non-linear magnetic field effects.
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- Award ID(s):
- 2008417
- PAR ID:
- 10483854
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- The European Physical Journal Special Topics
- Volume:
- 232
- Issue:
- 20-22
- ISSN:
- 1951-6355
- Format(s):
- Medium: X Size: p. 3197-3208
- Size(s):
- p. 3197-3208
- Sponsoring Org:
- National Science Foundation
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