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Title: Thermally induced nonlinear optical absorption in metamaterial perfect absorbers

A metamaterial perfect absorber consisting of a tri-layer (Al/ZnS/Al) metal-dielectric-metal system with top aluminium nano-disks was fabricated by laser-interference lithography and lift-off processing. The metamaterial absorber had peak resonant absorbance at 1090 nm and showed nonlinear absorption for 600ps laser pulses at 1064 nm wavelength. A nonlinear saturation of reflectance was measured to be dependent on the average laser power incident and not the peak laser intensity. The nonlinear behaviour is shown to arise from the heating due to the absorbed radiation and photo-thermal changes in the dielectric properties of aluminium. The metamaterial absorber is seen to be damage resistant at large laser intensities of 25 MW/cm{sup 2}.
Authors:
; ;  [1]
  1. Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India)
Publication Date:
OSTI Identifier:
22395750
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 11; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; ALUMINIUM; DAMAGE; DIELECTRIC MATERIALS; DIELECTRIC PROPERTIES; HEATING; INTERFERENCE; LASER RADIATION; LAYERS; NONLINEAR PROBLEMS; SPECTRAL REFLECTANCE; WAVELENGTHS; ZINC SULFIDES