Spheroidal nanoparticles as thermal near-field sensors

Biehs, Svend‐Age; Huth, Oliver; Rüting, Felix; Holthaus, Martin

doi:10.1063/1.3437651

Cited by 11 publications

(15 citation statements)

References 32 publications

(64 reference statements)

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“…When a particle is heated, it exchanges energy with the environment and cools down. In free space and assuming the surroundings at zero temperature, the spectral power lost by the particle (temperature T t , modelled by a dipole) is [50] P (ω) = ω 3 π 2 ǫ 0 c 3 ℑ[α(ω)]Θ(ω, T t ) (45) where Θ(ω, T t ) is again the mean thermal energy of the dipole oscillator. When the particle is close to a surface, the transferred power depends on the electromagnetic mode density at the particle position (EM LDOS) and can be much larger than in free space because non-radiative channels (evanescent modes) open up.…”

Section: (Non)radiative Cooling Of a Particlementioning

confidence: 99%

Strong tip–sample coupling in thermal radiation scanning tunneling microscopy

Joulain

Ben‐Abdallah

Chapuis

et al. 2014

Journal of Quantitative Spectroscopy and Radiative Transfer

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We analyze how a probing particle modifies the infrared electromagnetic near field of a sample.The particle, described by electric and magnetic polarizabilities, represents the tip of an apertureless scanning optical near-field microscope (SNOM). We show that the interaction with the sample can be accounted for by ascribing to the particle dressed polarizabilities that combine the effects of image dipoles with retardation. When calculated from these polarizabilities, the SNOM signal depends only on the fields without the perturbing tip. If the studied surface is not illuminated by an external source but heated instead, the signal is closely related to the projected electromagnetic local density of states (EM-LDOS). Our calculations provide the link between the measured farfield spectra and the sample's optical properties. We also analyze the case where the probing particle is hotter than the sample and evaluate the impact of the dressed polarizabilities on nearfield radiative heat transfer. We show that such a heated probe above a surface performs a surface spectroscopy, in the sense that the spectrum of the heat current is closely related to the local electromagnetic density of states. The calculations agree well with available experimental data.

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Section: (Non)radiative Cooling Of a Particlementioning

confidence: 99%

Strong tip–sample coupling in thermal radiation scanning tunneling microscopy

Joulain

Ben‐Abdallah

Chapuis

et al. 2014

Journal of Quantitative Spectroscopy and Radiative Transfer

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“…Somewhat more applied studies have attempted to take advantage of the potential of the tremendous increase of the radiative heat flux on the nanoscale for thermal imaging of nanostructured surfaces [21][22][23][24].…”

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confidence: 99%

Modulation of near-field heat transfer between two gratings

Biehs

Rosa

Ben‐Abdallah

2011

Applied Physics Letters

164

101

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We present a theoretical study of near-field heat transfer between two uniaxial anisotropic planar structures. We investigate how the distance and relative orientation (with respect to their optical axes) between the objects affect the heat flux. In particular, we show that by changing the angle between the optical axes it is possible in certain cases to modulate the net heat flux up to 90% at room temperature, and discuss possible applications of such a strong effect. 1Since the prediction by Polder and van Hove [1] that the heat exchange between two media at short separations can be much higher than the blackbody limit, numerous works have been carried out to investigate both theoretically and experimentally the physics involved in this transfer. Experimentally, it was shown [2,3] that the radiative heat flux increases for distances shorter than the thermal wavelength and can vastly exceed the black body limit [4,5]. Moreover, very recent experiments [6,7] were in good quantitative agreement with theoretical predictions. On the theoretical side, we can highlight the studies of the heat flux for layered media [8,9], for photonic crystals [10], metamaterials [11], and porous media [12].In addition, the dependence of the heat transfer on the geometry has attracted much interest and has been investigated in a sphere-plane geometry [13,14], for spheroidal particles above a plane surface [15] and between two spheres or nanoparticles [16][17][18][19][20]. Somewhat more applied studies have attempted to take advantage of the potential of the tremendous increase of the radiative heat flux on the nanoscale for thermal imaging of nanostructured surfaces [21][22][23][24].Finally, the formulation of the heat flux in terms of the scattering matrix [25,26] [33] to modulate heat flux between two materials using an electric ac current as external power source. However, due to the properties of these materials, such modulator works reversibly only during a limited number of cycle which typically oscillate between 10 7 and 10 12 . Moreover, such devices work at two discrete levels of flux, one for each state of the phase changing material.In this Letter, we investigate the near-field heat transfer between two polar/metallic misaligned gratings in the long wavelength limit, where they may be described by effective homogeneous anisotropic permittivities. We show that it is possible to get a strong heat flux modulation without cycle limitation just by rotating the relative position of the grating's 2 optical axes [34]. Our approach combines the standard stochastic electrodynamics [35] and the effective medium theory [36][37][38] for the gratings.A sketch of the geometry considered is depicted in Fig. 1. It shows two semi-infinite host materials of complex permittivity ǫ i (ω) (i = 1, 2) with a one dimensional grating engraved on each. The relative orientation of the two gratings is arbitrary in the (x,y) plane, and we assume that their trenches are sufficiently deep so as to (i) render the substrate below those gratings i...

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“…Note, that this expression is strictly valid for surface tip distances much larger than the tip radius only assuming a spherical metallic sensor tip. Indeed the value of the heat flux as well as the thermal near-field image of a structured surface depend on the shape and the material properties of the tip apex as was shown for ellipsoidal sensor tips (dielectric and metallic) in (Biehs et al (2010b); ). Hence, for a more refined model it is important to account for the sensor shape and to include the contributions of higher multipoles.…”

Section: Thermal Imagingmentioning

confidence: 99%