Speaker
Description
Wavelength-selective thermal emitters (WS-EMs) are of great interest as cost-effective light sources in the mid-infrared. WS-EMs can be achieved by Tamm plasmon polariton (TPPs) devices, which consist of a distributed Bragg reflector (DBR) on metal films. It has been shown that a TPP emitter can produce narrowband mid-IR emission [1]. However, in previous works, each device generally produced the narrowband emission at only one or few wavelengths. Here, we demonstrate a multi-channel wavelength-selective thermal emitter based on a Tamm plasmon polariton structure operating in the mid-IR region. In our approach, a single chip contains multiple emitting regions, with each having an emissivity spectrum that peaks at a particular wavelength. This is achieved by varying the spacer layer thickness.
The structure consists of a tungsten (W) film on a silicon substrate, an amorphous silicon spacer layer and a silicon dioxide / amorphous silicon (a-Si) DBR stack. To achieve multiple narrowband emission spectra, the spacer is broken into 16 regions, with thicknesses ranging from 175 nm to 400 nm. We fabricate a 16-channel TPP emitter by first depositing the W film on a silicon substrate. Then, we employ the combinatorial deposition technique (CDT) to selectively deposit a-Si film as the spacer layer [2]. Finally, the DBR stack is deposited. We measure the reflectance and emission spectra of the 16-channel TPP emitter. The centre wavelengths of the emission peaks are in good agreement with the reflectance dip, which covers the wavelength range from ~3.3 μm to 4.2 μm, with an average emissivity of ~0.75. We plan to demonstrate the spectral classification of everyday plastic products and spectral reconstruction using this multi-channel emitter.
[1] Yang et al., ACS Photonics 4, 2212–2219 (2017).
[2] S.-W. Wang et al., Appl. Phys. B 88, 281–284 (2007).
| I am the presenting author | Yes |
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