Millimeter-wave broadband antireflection coatings using laser ablation of subwavelength structures.

  title={Millimeter-wave broadband antireflection coatings using laser ablation of subwavelength structures.},
  author={Tomotake Matsumura and Karl Young and Qi Wen and Shaul Hanany and Hirokazu Ishino and Yuki Inoue and Masashi Hazumi and J{\"u}rgen Koch and Oliver Suttman and Viktor Sch{\"u}tz},
  journal={Applied optics},
  volume={55 13},
We report on the first use of laser ablation to make submillimeter, broadband, antireflection coatings (ARCs) based on subwavelength structures (SWSs) on alumina and sapphire. We used a 515 nm laser to produce pyramid-shaped structures with a pitch of about 320 μm and a total height of near 800 μm. Transmission measurements between 70 and 140 GHz are in agreement with simulations using electromagnetic propagation software. The simulations indicate that SWS-ARCs with the fabricated shape should… 

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