Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Amemiya, Kuniaki*; Koshikawa, Hiroshi; Yamaki, Tetsuya; Maekawa, Yasunari; Shitomi, Hiroshi*; Kinoshita, Kenichi*; Numata, Takayuki*; Tanabe, Minoru*; Fukuda, Daiji*
no journal, ,
A thermal radiometer absorbs all incoming photons and has a high sensitivity to detect the resulting temperature rise. The big challenges here were insufficient mechanical stability of broadband ultra-black absorbers and low sensitivity of photo-thermal sensors. We developed a robust optical absorber and low-noise photo-thermal sensor by new microfabrication techniques. The optical absorbers had micrometer-sized surface structures of chemically-etched ion tracks on CR-39 plastic and hard carbon coating as an optical absorption layer, therefore, exhibiting a spectral reflectance suppressed to below 1% in the ultra-violet to near infrared range of wavelengths. Importantly, they were never made susceptible to dust blow off as well as to mechanical contact. The photo-thermal detectors were equipped with the bimetal MEMS system, which can sensitively respond to thermally-induced deformation. They were found sensitive enough to reach almost the theoretical limit.
Amemiya, Kuniaki*; Koshikawa, Hiroshi; Yamaki, Tetsuya; Maekawa, Yasunari; Shitomi, Hiroshi*; Kinoshita, Kenichi*; Numata, Takayuki*; Tanabe, Minoru*; Fukuda, Daiji*
no journal, ,
The novel broadband near-perfect black absorber for an absolute radiometer has been developed. Microstructured surface having high-aspect-ratio conical pores was fabricated by swift heavy ion beam irradiation and following etching process; subsequently, the surface was coated with black layer. Incident light which enters into the surface microstructure experiences multiple reflections which enhance optical absorption; therefore, the net reflectance decreases much less than 1% with sufficient pit aspect ratio and absorption layer thickness, which can be designed by finite differential time domain (FDTD) method calculation. Furthermore, a prototype of the novel black absorber also exhibited good mechanical durability. This newly developed black material is also expected to have potential application in various fields of optical energy management such as stray light elimination.