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Research project

Next generation meta-material based SMART and FLEXible optical solar reflectors

Project overview

The SMART-FLEX OSR is an extremely thin, fully inorganic, metamaterial coating deposited on the first, space-facing surface of a flexible foil, that can be easily glued on the outer skin of radiator panels, or of any other curved or bendable structure directly exposed to the space environment.

The foil rejects solar radiation, and regulates passively – without the intervention of the thermal control system – the heat exchanged between the satellite and the space environment, so avoiding overheating in the hot phase, and overcooling when the satellite is in eclipse or in safe mode.

The coating consists primarily of a three-layer structure known – in the jargon of the plasmonic community -as a Perfect Metamaterial Absorber (PMA): a metal ground-plane (bottom layer), a dielectric spacer, and a 2D array of nano-antennas made of thermochromic material.

At high temperatures, the interaction between the conductive nano-antennas and the ground plane generates close to unit broadband absorption in the thermal IR (that is high emissivity), matched to high reflectivity in the solar spectrum.

Below the transition temperature of the thermochromic material, the nano-antennas become dielectric and plasmonic resonance is inhibited, causing a substantial reduction of emissivity.

The PMA can be completed with a few additional layers grown on top of the nano-antennas, that improve the thermo-optical performance of the coating and provide protection against ageing and electro-static discharge.


Lead researcher

Professor Otto Muskens

Professor of Physics

Research interests

  • Programmable photonic circuits using ultralow loss phase change materials.
  • Infrared metasurfaces for radiative cooling and defence applications.
  • Deep learning and AI enabled nanophotonic design.
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Other researchers

Professor Kees De Groot


Research interests

  • Radio-Frequency and Microwave Devices
  • 2 dimensional Transition Metal Dichalcogenides  Transistors
  • Smart Radiative Cooling and RF control of smart glass using metal oxides such as Al-doped ZnO and W-doped VO2
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Collaborating research institutes, centres and groups

Research outputs