Spatially Resolved Dynamically Reconfigurable Multilevel Control of Thermal Emission

Xu, Zhifei; Li, Qiang; Du, Kaikai; Long, Shiwei; Yang, Yang; Cao, Xun; Luo, Hao; Zhu, Huanzheng; Ghosh, Pintu; Shen, Weidong; Qiu, Min

doi:10.1002/lpor.201900162

Cited by 122 publications

(81 citation statements)

References 47 publications

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“…is the power spectral density per unit area radiated by a perfect black body, h is the Planck's constant, c is the speed of light in vacuum, k B is the Boltzmann constant, λ min and λ max represent the lower and upper limit of the detected wavelength range, respectively 36 .…”

Section: Resultsmentioning

confidence: 99%

“…3 a,b with markers and the solid curves show simulation results. The overall emitted signal S sample integrated on the camera wavelength range (3.3–5.1 microns) and normalized with respect to the reference perfect blackbody emitter (S ref —reference graphite paint) can be interpreted as an average effective relative emissivity of the system in the camera wavelength range ε eff ( T ) according to: where is the power spectral density per unit area radiated by a perfect black body, h is the Planck's constant, c is the speed of light in vacuum, k B is the Boltzmann constant, λ min and λ max represent the lower and upper limit of the detected wavelength range, respectively 36 .…”

Section: Resultsmentioning

confidence: 99%

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Adaptive tuning of infrared emission using VO2 thin films

Larciprete

Centini

Paoloni

et al. 2020

Sci Rep

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Phase-transition materials provide exciting opportunities for controlling optical properties of photonic devices dynamically. Here, we systematically investigate the infrared emission from a thin film of vanadium dioxide (VO 2). We experimentally demonstrate that such thin films are promising candidates to tune and control the thermal radiation of an underlying hot body with different emissivity features. In particular, we studied two different heat sources with completely different emissivity features, i.e. a black body-like and a mirror-like heated body. The infrared emission characteristics were investigated in the 3.5-5.1 μm spectral range using the infrared thermography technique which included heating the sample, and then cooling back. Experimental results were theoretically analyzed by modelling the VO 2 film as a metamaterial for a temperature range close to its critical temperature. Our systematic study reveals that VO 2 thin films with just one layer 80 nm thick has the potential to develop completely different dynamic tuning of infrared radiation, enabling both black-body emission suppression and as well as mirror emissivity boosting, in the same single layer device. Understanding the dynamics and effects of thermal tuning on infrared emission will benefit wide range of infrared technologies including thermal emitters, sensors, active IR filters and detectors. The possibility to tune the spectral features of a device, triggered by a thermal, electrical or optical stimulation, paves the way for many applications such as perfect infrared absorbers 1-4 , smart intelligent window coatings 5,6 , thermal rectification devices 7 or diodes/rectifiers 8. Thermochromic materials, such as niobium dioxide (NbO 2), vanadium sesquioxide (V 2 O 3), and vanadium dioxide (VO 2) undergo an abrupt phase transition from semiconductor to metallic state at a specific phase transition temperature 9-11. This phase change transition, from insulating monoclinic phase into a metallic tetragonal (rutile) phase, is accompanied by drastic changes in electrical, optical and magnetic properties as a function of the temperature. Among them, VO 2 is widely employed since it pertains the lowest phase transition temperature, T c = 341 K (68 °C) 12. The strong and reproducible changes in optical properties due to phase transition, have generated a burgeoning amount of theoretical and experimental studies focusing on the thermal emissivity variation activated by temperature in VO 2 13,14 in the IR 15 and THz radiation ranges 16. The thermal hysteresis intrinsic to the phase transition has been widely investigated and was found to be affected by several factors such as the film deposition temperature 17 , the use of different substrates 18-20 , the wavelength range 21 , the introduction of metallic dopants 22 and the dimensions of metallic grains 23. In particular, if metallic grain size is smaller than the wavelength of excitation, diffraction effects result in enhanced transmitted signal. When temperature increases, the grain sizes of exp...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Adaptive tuning of infrared emission using VO2 thin films

Larciprete

Centini

Paoloni

et al. 2020

Sci Rep

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“…To control the surface emittance, nanostructure-based surfaces (e.g., metasurfaces 3,8 and metallic-dielectric nanowires 9 ) or films (metal 10 , semiconductor 11,12 , and multilayer films [13][14][15][16][17] ) are demonstrated with low-surface emittance over the whole IR range, and yet the radiative heat transfer is blocked, causing severe heat instability 18 . Wavelength-selective emitters [19][20][21][22][23][24][25] with radiative cooling [26][27][28][29][30][31] in the non-atmospheric window (5-8 μm) 18,20,32 are adopted to mitigate the heat instability without influencing the IR camouflage.…”

Section: Introductionmentioning

confidence: 99%

High-temperature infrared camouflage with efficient thermal management

et al. 2020

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High-temperature infrared (IR) camouflage is crucial to the effective concealment of high-temperature objects but remains a challenging issue, as the thermal radiation of an object is proportional to the fourth power of temperature (T 4). Here, we experimentally demonstrate high-temperature IR camouflage with efficient thermal management. By combining a silica aerogel for thermal insulation and a Ge/ZnS multilayer wavelength-selective emitter for simultaneous radiative cooling (high emittance in the 5-8 μm non-atmospheric window) and IR camouflage (low emittance in the 8-14 μm atmospheric window), the surface temperature of an object is reduced from 873 to 410 K. The IR camouflage is demonstrated by indoor/outdoor (with/without earthshine) radiation temperatures of 310/248 K for an object at 873/623 K and a 78% reduction in with-earthshine lock-on range. This scheme may introduce opportunities for high-temperature thermal management and infrared signal processing.

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“…Representative PCMs such as VO 2 [17][18][19][20][21][22][23][24][25][26][27][28][29], Ge 2 Sb 2 Te 5 (GST) [30][31][32][33][34][35][36][37][38][39][40][41], SmNiO 3 [42] have been thoroughly studied with the application of external thermal, electrical, and optical signal for the last decade. These PCMs were integrated to metamaterial and metasurface structures for dynamically tunable extraordinary responses of optical wavefront, spectrum, and polarization within ultrathin thickness, particularly, in the mid [28,29,[39][40][41][42] and nearinfrared [18-20, 26, 27, 30-34] and visible range [35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Dynamic phase-change metafilm absorber for strong designer modulation of visible light

et al. 2020

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AbstractEffective dynamic modulation of visible light properties has been significantly desired for advanced imaging and sensing technologies. In particular, phase-change materials have attracted much attention as active material platforms owing to their broadband tunability of optical dielectric functions induced by the temperature-dependent phase-changes. However, their uses for visible light modulators are still limited to meet multi-objective high performance owing to the low material quality factor and active tunability in the visible regime. Here, a design strategy of phase-change metafilm absorber is demonstrated by making the use of the material drawbacks and extending design degree of freedom. By engineering tunability of effective anisotropic permittivity tensor of VO2-Ag metafilm around near-unity absorption conditions, strong dynamic modulation of reflection wave is achieved with near-unity modulation depth at desired wavelength regions without sacrificing bandwidth and efficiency. By leveraging effective medium theory of metamaterial and coupled mode theory, the intuitive design rules and theoretical backgrounds are suggested. It is also noteworthy that the dynamic optical applications of intensity modulation, coloring, and polarization rotation are enabled in a single device. By virtue of ultrathin flat configuration of a metafilm absorber, design extensibility of reflection spectrum is also verified. It is envisioned that our simple and powerful strategy would play a robust role in development of miniaturized light modulating pixels and a variety of photonic and optoelectronic applications.

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Spatially Resolved Dynamically Reconfigurable Multilevel Control of Thermal Emission

Cited by 122 publications

References 47 publications

Adaptive tuning of infrared emission using VO2 thin films

Adaptive tuning of infrared emission using VO2 thin films

High-temperature infrared camouflage with efficient thermal management

Dynamic phase-change metafilm absorber for strong designer modulation of visible light

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