Selective absorbers and emitters
Surfaces with narrow-band high absorption efﬁciency are particularly desirable for various applications including monochromatic photodetectors and coherent thermal emitters. Efficient light absorbers based on metamaterials and plasmonic nanostructures have received increased attention in the recent literature. First a narrow-band absorbing metamaterial at microwave regime was proposed . Later different concepts were presented for visible and infrared wavelengths based on lithographic partnering of the metallic surface and nanowire metamaterial [2-4]. All these approaches would require a consuming lithographic partnering of the surface. In contrast to the absorbers prepared by lithography, a low-cost fabrication method based on colloidal crystals has been utilized to produce large area structures with near perfect light absorption [5,6].
The research in the institute for Optical and Electronic Materials is concentrated on designing a broadband and narrowband absorbers and emitters that can operate at high temperature (> 1000°C). The goal is to realize such a high temperature absorbers and emitters with following properties:
- High thermal stability (> 1000°C).
- High emissivity in desirable range independent of angle and polarization.
- Finite Element Method (MWS CST)
- Finite Difference Time Domain (MEEP)
- Self-assembly of colloidal micro-particles
- Magnetron deposition
- Structural characterization with Scanning electron microscope (SEM) & optical microscopy
- Reflectance measurement with UV-Vis and FTIR spectrometers.
- Emission measurement with FTIR spectrometer
We design and investigate a perfect narrow-band absorber with reconfigurable band position from 1.2 µm to 2.6 µm. As illustrated in Fig. 1, the designed absorber consists of a two-dimensional hexagonal array of metallodielectric core-shell microspheres on a gold substrate. We have studied how two-dimensional arrays of metallodielectric core-shell microspheres on a metal substrate can efﬁciently absorb infrared electromagnetic radiation in a narrow wavelength range under normal incidence. The results are shown in Fig. 2 for R = 700 nm and different rc. Perfect absorbance can be obtained for the peak at wavelength λ1 = 1.7 µm. Smaller or larger core size lead to smaller absorption level. Also, as rc increases, the first absorption peak is red shifted.
| || |
Fig. 1 The unit cell of a two-dimensional hexagonal array of metallodielectric core-shell microspheres on the gold substrate. Inset shows a diagram of a hexagonal array.
Fig. 2 Calculated absorption under the assumption of normal incidence for narrow-band absorbers with R = 700 nm and rc = 125, 150, 175, 200 and 225 nm.
List of publications
Dyachenko P. N.; Petrov, A. Yu.; and Eich M., “Perfect narrow-band absorber based on a monolayer of metallodielectric microspheres”, Appl. Phys. Lett. 103, 211105 (2013).
Dr. Michael Störmer
Helmholtz-Zentrum Geesthacht Centre for Materials and Coastal Research, Institute of Materials Research
Dr. Tobias Vossmeyer and Prof. Dr.Horst Weller
University of Hamburg, Institute of Physical Chemistry
1. Landy, N. I.; Sajuyigbe, S.; Mock, J. J.; Smith D. R.; and Padilla, W. J., Phys. Rev. Lett. 100, 207402 (2008).
2. Hao, J. M.; Wang, J.; Liu, X. L.; Padilla, W. J.; Zhou L. and Qiu, M., Appl. Phys. Lett. 96, 251104 (2010).
3. Han, S. E.; and Norris D. J., Opt. Express 18, 4829 (2010).
4. He, Y.; Deng, H.; Jiao, X.; He, S.; Gao, J.; and Yang, X., Opt. Lett. 38, 1179 (2013).
5. Teperik, T. V.; García de Abajo, F. J. ; Borisov, A. G. ; Abdelsalam, M.; Bartlett, P. N.; Sugawara, Y.; and Baumberg, J. J., Nat. Photonics 2, 299 (2008).
6. Moreau, A.; Ciracì, C.; Hill, R. T.; Mock, J. J.; Wang, Q.; Wiley, B. Chilkoti, J.;A. ; and Smith, D. R., Nature 492, 86 (2012).