Anisotropic metamaterial with only one component of the mass density tensor near zero （ADNZ） is proposed to control the sound wave propagation. We find that such an anisotropic metamaterial can be used to realize pe...Anisotropic metamaterial with only one component of the mass density tensor near zero （ADNZ） is proposed to control the sound wave propagation. We find that such an anisotropic metamaterial can be used to realize perfect bending waveguides. According to a coordinate transformation, the surface waves on the input and output interfaces of the ADNZ metamaterial induces the sound energy flow to be redistributed and match smoothly with the propagating modes inside the metamaterial waveguide. According to the theory of bending waveguide, we realize the ＂T＂-type sound shunting and convergence, as well as acoustic channel selection by embedding small-sized defects. Numerical calculations are performed to confirm the above effects.展开更多
We present a 1 × 4 Y-branch digital optical switch in which S-bend variable optical attenuators are integrated. The S-bend waveguides, which are always introduced to connect the switch and the standard fiber arra...We present a 1 × 4 Y-branch digital optical switch in which S-bend variable optical attenuators are integrated. The S-bend waveguides, which are always introduced to connect the switch and the standard fiber array, are made use of and designed as variable optical attenuators. A compact device with low crosstalk and larger branching-angle is obtained. The device is fabricated on the thermo-optic polymer materials,and the performance of the device is measured. With an applied driving power of less than 200mW, the device has a low crosstalk of less than - 35dB at a wavelength of 1.55 μm.展开更多
The scattering behavior of an anisotropic acoustic medium is analyzed to reveal the possibility of routing acoustic signals through the anisotropic layers with no backscattering loss. The sound-transparent effect of s...The scattering behavior of an anisotropic acoustic medium is analyzed to reveal the possibility of routing acoustic signals through the anisotropic layers with no backscattering loss. The sound-transparent effect of such a medium is achieved by independently modulating the anisotropic effective acoustic parameters in a specific order, and is experimentally observed in a bending waveguide by arranging the subwavelength structures in the bending part according to transformation acoustics. With the properly designed filling structures, the original distorted acoustic field in the bending waveguide is restored as if the wave travels along a straight path. The transmitted acoustic signal is maintained nearly the same as the incident modulated Gaussian pulse. The proposed schemes and the supporting results could be instructive for further acoustic manipulations such as wave steering, cloaking and beam splitting.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2012CB921504)the National Natural Science Foundation of China(Grant No.11474160)+2 种基金the Fundamental Research Funds for the Central Universities,China(Grant No.020414380001)the State Key Laboratory of Acoustics,Chinese Academy of Sciences(Grant No.SKLA201609)the Priority Academic Program Development of Jiangsu Higher Education Institution,China
文摘Anisotropic metamaterial with only one component of the mass density tensor near zero （ADNZ） is proposed to control the sound wave propagation. We find that such an anisotropic metamaterial can be used to realize perfect bending waveguides. According to a coordinate transformation, the surface waves on the input and output interfaces of the ADNZ metamaterial induces the sound energy flow to be redistributed and match smoothly with the propagating modes inside the metamaterial waveguide. According to the theory of bending waveguide, we realize the ＂T＂-type sound shunting and convergence, as well as acoustic channel selection by embedding small-sized defects. Numerical calculations are performed to confirm the above effects.
文摘We present a 1 × 4 Y-branch digital optical switch in which S-bend variable optical attenuators are integrated. The S-bend waveguides, which are always introduced to connect the switch and the standard fiber array, are made use of and designed as variable optical attenuators. A compact device with low crosstalk and larger branching-angle is obtained. The device is fabricated on the thermo-optic polymer materials,and the performance of the device is measured. With an applied driving power of less than 200mW, the device has a low crosstalk of less than - 35dB at a wavelength of 1.55 μm.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11974186,11604153,and 61975080)the Natural Science Foundation of Jiangsu Province,China(Grant Nos.BK20160818 and BK20200070)the Open Research Foundation of Key Laboratory of Modern Acoustics,Ministry of Education。
文摘The scattering behavior of an anisotropic acoustic medium is analyzed to reveal the possibility of routing acoustic signals through the anisotropic layers with no backscattering loss. The sound-transparent effect of such a medium is achieved by independently modulating the anisotropic effective acoustic parameters in a specific order, and is experimentally observed in a bending waveguide by arranging the subwavelength structures in the bending part according to transformation acoustics. With the properly designed filling structures, the original distorted acoustic field in the bending waveguide is restored as if the wave travels along a straight path. The transmitted acoustic signal is maintained nearly the same as the incident modulated Gaussian pulse. The proposed schemes and the supporting results could be instructive for further acoustic manipulations such as wave steering, cloaking and beam splitting.
