We report a heptad vortex array structure in the wave fields in an extremely deep Fresnel diffraction region by asymmetrical subwavelength holes in a metal film illuminated with linearly polarized light. A Mach Zehnde...We report a heptad vortex array structure in the wave fields in an extremely deep Fresnel diffraction region by asymmetrical subwavelength holes in a metal film illuminated with linearly polarized light. A Mach Zehnder interferometer with a microscopic objective is used to record the wave fields at different distance＆ and the phase maps are extracted by Fourier transform of the interference intensities. We study the evolutions of the heptad vortex array with distance from the sample to the object plane. To explain the formations and the evolutions of the vortex array, we calculate the diffracted wave fields with Kirchhoff＇s diffraction theory. The calculations are basically consistent with the experimental results, and the properties of the heptad vortex array structure are reasonably explained.展开更多
The extraordinary light transmission through a 200-nm thick gold film when passing through different subwavelength hole arrays is observed experimentally. The sample is fabricated by electron beam lithography and reac...The extraordinary light transmission through a 200-nm thick gold film when passing through different subwavelength hole arrays is observed experimentally. The sample is fabricated by electron beam lithography and reactive ion etching system. A comparison between light transmissions shows that the hole shape changing from rectangular to diamond strongly affects the transmission intensity although both structures possess the same lattice constant of 600 nm. Moreover, the position of the transmission maximum undergoes a spectral red-shift of about 63 nm. Numerical simulations by using a transfer matrix method reproduce the observed transmission spectrum quite well.展开更多
Light passing through a subwavelength hole in an opaque plate is a fundamental concern in both optical science and applications.Using both simulations and experiments,we show that,when a subwavelength hole in a silver...Light passing through a subwavelength hole in an opaque plate is a fundamental concern in both optical science and applications.Using both simulations and experiments,we show that,when a subwavelength hole in a silver thin film is surrounded by well-designed patterns of grooves,the wavefront of the infrared light through it can be shaped into a preset complicated pattern such as a Latin letter‘L’or‘O’at a given position instead of being diffracted in all directions.The design is created via the surface-wave-holography method,which allows direct determination of the surface plasmonic structure for a given wavefront-engineering functionality without the need to solve complex inverse problems.The results will deepen current understanding of this enduring issue and will find applications in many fields such as wave manipulation and sensing.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11574185the Science and Technology Development Program of Shandong Province under Grant No 2009GG10001005
文摘We report a heptad vortex array structure in the wave fields in an extremely deep Fresnel diffraction region by asymmetrical subwavelength holes in a metal film illuminated with linearly polarized light. A Mach Zehnder interferometer with a microscopic objective is used to record the wave fields at different distance＆ and the phase maps are extracted by Fourier transform of the interference intensities. We study the evolutions of the heptad vortex array with distance from the sample to the object plane. To explain the formations and the evolutions of the vortex array, we calculate the diffracted wave fields with Kirchhoff＇s diffraction theory. The calculations are basically consistent with the experimental results, and the properties of the heptad vortex array structure are reasonably explained.
基金Project supported by National Natural Science Foundation of China Special Foundation of China （Grant Nos 2001CB6104 and 2003CB7169） Sciences, China. （Grant No 10525419）, the National Key Basic Research and the Presidential Foundation of the Chinese Academy Sciences, China.
文摘The extraordinary light transmission through a 200-nm thick gold film when passing through different subwavelength hole arrays is observed experimentally. The sample is fabricated by electron beam lithography and reactive ion etching system. A comparison between light transmissions shows that the hole shape changing from rectangular to diamond strongly affects the transmission intensity although both structures possess the same lattice constant of 600 nm. Moreover, the position of the transmission maximum undergoes a spectral red-shift of about 63 nm. Numerical simulations by using a transfer matrix method reproduce the observed transmission spectrum quite well.
基金This work was supported by the National Basic Research Foundation of China under grant no.2011CB922002 and Knowledge Innovation Program of the Chinese Academy of Sciences(No.Y1V2013L11).
文摘Light passing through a subwavelength hole in an opaque plate is a fundamental concern in both optical science and applications.Using both simulations and experiments,we show that,when a subwavelength hole in a silver thin film is surrounded by well-designed patterns of grooves,the wavefront of the infrared light through it can be shaped into a preset complicated pattern such as a Latin letter‘L’or‘O’at a given position instead of being diffracted in all directions.The design is created via the surface-wave-holography method,which allows direct determination of the surface plasmonic structure for a given wavefront-engineering functionality without the need to solve complex inverse problems.The results will deepen current understanding of this enduring issue and will find applications in many fields such as wave manipulation and sensing.
