By Peixun Fan and Minlin Zhong

Infrared antireflection surfaces are of great realistic significance in wide fields including infrared imaging, sensors, thermoelectrics, stealth, artificial blackbody, etc. However, efficient infrared antireflection property still remains a major challenge, especially on metal surfaces which are usually inherent excellent reflectors at the infrared wavelength regime. Until now, few reports of near unity infrared AR property reaching reflectance below 1 percent and fewer reports of broadband near unity AR strategies which keep effective through the spectrum of 5~25 μm on metal surfaces have been demonstrated. It is known that the high optical impedance between metal and the free space is the culprit accounting for the severe apparent reflection of metal surfaces. An effective method for alleviating the optical impedance is to introduce a transitional medium. The semiconductor materials, metal oxide in particular, are expected to be good candidates to realize such a purpose. However, it’s technically difficult to steadily produce a uniform as well as highly efficient oxide layer on metal surfaces. Here, we propose a novel ultrafast laser hybrid processing approach to tackle this fundamental challenge. By forming precursor micro-nano structures via ultrafast laser, oxide in the unique structural form of nanowires is facilely and uniformly grown on Cu surfaces after a subsequent simple thermal oxidation process. Continue reading →