FIG. 1. a) Absorption spectrum of the absorber. b) SEM image of gold nanorods on top. The scale bar is 200 nm. Solar cells NIR imaging FIG. 2. Absorption under p-polarized light. Inset is simplified structure. (a) schematic of the broadband absorber, the yellow region is gold and blue regions are dielectric. (b) cross-section of half a unit cell. A broadband absorber based gratings is numerically demonstrated, and an average absorption efficiency of 88% is achieved over a wide range of wavelengths (700-2300 nm) for p-polarized light. Blue regions are alumina, the yellow is gold. a = 100 nm, w = 80 nm, and H = 50 nm. In the simulations, half a unit cell consists of 40 grooves, i. e, the width of half a unit is 4000 nm and the depth of the deepest groove is 2000 nm.
Pro. Min Qiu, Dr. Qiang Li, Xingxing Chen, Lijun Meng, Ding Zhao, Hanmo Gong 仇旻教授，李强副教授，陈星星，孟力俊，赵鼎，龚翰墨 [1] X. X. Chen et al., Opt. Lett. 38, 2247-2249 (2013) [2] L. J. Meng et al., Opt. Express 21, A111-A122 (2013) [3] L. J. Meng et al., Opt. Lett. 39, 1137-1140 (2014) [4] D. Zhao et al., Appl. Phys. Lett. 104, 221107 (2014)
(b)
FIG. 2. (a-c) Schematic of the optimized structure. a=1400nm, s=92nm, h=50nm, and r=25nm. (d) Absorption spectra as a function of the environmental refractive index.
Ultra-narrow band absorber
(a) (c) (d)
[3,4] A ultra-narrow band absorber with high absorption is investigated. According to Kirchhoff’s law, the perfect absorber can be considered as a highly directional thermal emitter with an angular width of 0.4 mrad at 1900 nm. The structure presented here has great potential as a light source, satellite radar, sensors, etc.
Broadband absor来自er[1,2] (a) (b)
An extremely broadband absorber is fabricated using droplet evaporation method. Such a metasurface may provide possibilities for obtaining large-area light absorbers in applications such as photothermalvoltaics, NIR imaging, sensing, etc.
光学超材料吸收器
Optical Metamaterial Absorber
Turning the surfaces of metals (metasurfaces) into black (highly absorptive) surfaces has been an attractive research topic. Efficient and tunable absorption of metamaterials based on noble metal has been investigated extensively and developed in a variety of branches. Our research efforts are thus focused on designing optical absorber with novel functionalities.
Light source
Satellite radar
Sensors
An ultra-narrow band absorber consisting of continuous silver and alumina films is investigated. Owing to Fabry–Perot resonance and silver’s inherent loss, an ultra-narrow spectral range of light can be entirely trapped in the structure. FIG. 3. Calculated and measured absorption of the narrowband absorber consisting of multilayer films. The thicknesses from top to bottom are 60 nm, 150 nm, 10 nm and 150 nm, respectively. The scale bar is 200 nm. Main researchers : References