A microwave metamaterial shelter with an electromagnetic narrow window over a broad absorption spectrum is experimentally demonstrated by resorting to conventional impedance-matching theory and metamaterial resonance....A microwave metamaterial shelter with an electromagnetic narrow window over a broad absorption spectrum is experimentally demonstrated by resorting to conventional impedance-matching theory and metamaterial resonance.This device consists of a broad absorber and an embedded electric resonator,and has the ability of permitting one to"see"surroundings but not to be readily sensed by outside detectors.The origin is verified to be a dipole oscillation excited in absorbing region which can induce selective re-emission of the captured energy towards the enclosed space.The performance of"observing without being perceived"is numerically presented.展开更多
A cross-linkable fluorinated poly (ether ether ketone) (FPEEK) was synthesized for the fabrication of arrayed waveguide grating (AWG) multiplexer. The results of thermal gravimetric analysis (TGA) and near-infrared ab...A cross-linkable fluorinated poly (ether ether ketone) (FPEEK) was synthesized for the fabrication of arrayed waveguide grating (AWG) multiplexer. The results of thermal gravimetric analysis (TGA) and near-infrared absorption spectrum show that the materials have high thermal stability and high optical transparency in the infrared communication region. The refractive index of FPEEK can be controlled easily by changing the fluorine content of the materials. The 32-channel AWG multiplexer is fabricated using the FPEEK and oxygen reactive ion etching technology. The AWG multiplexer exhibits that the insertion loss is from 12.8 to 17.8 dB and the channel crosstalk is less than-20 dB. The wavelength channel spacing and the center wavelength are 0.8nm and 1548nm, respectively.展开更多
基金supported by the National Basic Research Program (973) of China under Grant (2013CBA 01700)
文摘A microwave metamaterial shelter with an electromagnetic narrow window over a broad absorption spectrum is experimentally demonstrated by resorting to conventional impedance-matching theory and metamaterial resonance.This device consists of a broad absorber and an embedded electric resonator,and has the ability of permitting one to"see"surroundings but not to be readily sensed by outside detectors.The origin is verified to be a dipole oscillation excited in absorbing region which can induce selective re-emission of the captured energy towards the enclosed space.The performance of"observing without being perceived"is numerically presented.
文摘A cross-linkable fluorinated poly (ether ether ketone) (FPEEK) was synthesized for the fabrication of arrayed waveguide grating (AWG) multiplexer. The results of thermal gravimetric analysis (TGA) and near-infrared absorption spectrum show that the materials have high thermal stability and high optical transparency in the infrared communication region. The refractive index of FPEEK can be controlled easily by changing the fluorine content of the materials. The 32-channel AWG multiplexer is fabricated using the FPEEK and oxygen reactive ion etching technology. The AWG multiplexer exhibits that the insertion loss is from 12.8 to 17.8 dB and the channel crosstalk is less than-20 dB. The wavelength channel spacing and the center wavelength are 0.8nm and 1548nm, respectively.
