We show that perfect absorption can be achieved in a system comprising a single lossy dielectric layer of thickness much smaller than the incident wavelength on an opaque substrate by utilizing the nontrivial phase shifts at interfaces between lossy media. This design is implemented with an ultra-thin (∼λ/65) vanadium dioxide (VO2) layer on sapphire, temperature tuned in the vicinity of the VO2 insulator-to-metal phase transition, leading to 99.75% absorption at λ = 11.6 μm. The structural simplicity and large tuning range (from ∼80% to 0.25% in reflectivity) are promising for thermal emitters, modulators, and bolometers.
Ultra-thin perfect absorber employing a tunable phase change material
Mikhail A. Kats, Deepika Sharma, Jiao Lin, Patrice Genevet, Romain Blanchard, Zheng Yang, M. Mumtaz Qazilbash, D. N. Basov, Shriram Ramanathan, Federico Capasso; Ultra-thin perfect absorber employing a tunable phase change material. Appl. Phys. Lett. 26 November 2012; 101 (22): 221101. https://doi.org/10.1063/1.4767646
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