Ultra-broad band antireflection coating at mid wave infrared for high efficient germanium optics


Yenisoy A., YEŞİLYAPRAK C., Ruzgar K., TÜZEMEN S.

OPTICAL MATERIALS EXPRESS, cilt.9, sa.7, ss.3123-3131, 2019 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 9 Sayı: 7
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1364/ome.9.003123
  • Dergi Adı: OPTICAL MATERIALS EXPRESS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.3123-3131
  • Atatürk Üniversitesi Adresli: Evet

Özet

This work mainly demonstrates the development process of an ultra-broad band antireflection (AR) coating that maximizes the optical performance of germanium optical elements. A multilayer stack exhibiting high efficient AR performance on Ge consists of thin multi-layers of aluminum oxide (Al2O3) and germanium (Ge) named as low and high refractive index layer materials. A three-layer design with a very tight thickness tolerance (3%) was optimized by Optilayer software. Al2O3 and Ge layers were deposited by a plasma assisted e-beam evaporation system. Ultra-high efficient multilayer AR coating on Ge has a base reflectance 0.005% at 3550 nm and an average reflectance of 0.256% over the entire mid wave infrared spectrum. Multilayer AR coating on Ge offers lower base and average reflectance than the works reported before. Moreover, AR coating on Ge offers a cost effective process cycle due to its number of layers and its thickness for providing ultra-broadband and high efficient optical performance for mid wave infrared electro-optical applications. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement