The frequency selective surface (FSS) has been widely applied by means of its spatial frequency-filter characteristic, but it is always designed and used as a device with fixed frequency response. In order to tune the...The frequency selective surface (FSS) has been widely applied by means of its spatial frequency-filter characteristic, but it is always designed and used as a device with fixed frequency response. In order to tune the resonant frequency and switch the frequency channel, a scheme of mechanically tunable FSS is theoretically analyzed by using the method of Floquet's vector modes expansion and fields matching. A double-layer tunable FSS with dipole element can perform a dynamic range of resonant frequency covering whole X-band.展开更多
To resolve the problem of missed evanescent waves in a beam focusing system,a hyperlens-based beam focusing device is proposed in this letter.This device can convert the evanescent waves into propagating waves,and the...To resolve the problem of missed evanescent waves in a beam focusing system,a hyperlens-based beam focusing device is proposed in this letter.This device can convert the evanescent waves into propagating waves,and then a super-resolution spot is formed at the center of the hyperlens.The working principle of the device is presented,and the way in which the material and structural parameters of the hyperlens affect the resolution and transmission is analyzed in detail.A multibeam focusing device is optimally designed,and the simulated results verify that a nanoscale spot with a diameter of 15.6 nm（corresponding toλ0/24,whereλ0 is the working wavelength in vacuum）is achieved,which is far less than the diffraction limited resolution with a value of 625 nm（1.7λ0）.The device is expected to find numerous applications in optical data storage and nano-photolithography,among others.展开更多
The propagation of a filamentary laser beam at an air-glass surface is studied by setting the incident angle sat- isfying the total reflection condition. The images of the trajectory of the filamentary laser beam insi...The propagation of a filamentary laser beam at an air-glass surface is studied by setting the incident angle sat- isfying the total reflection condition. The images of the trajectory of the filamentary laser beam inside the sample and the output far-field spatial profiles are measured with varying incident laser pulse energies. Different from the general total reflection, a transmitted laser beam is detected along the propagation direction of the incident laser beam. The energy ratio of the transmitted laser beam depends on the pulse energies of the incident laser beam. The background energy reservoir surrounding the filament core can break the law of total reflection at the air-glass surface, resulting in the regeneration of the transmitted laser beam.展开更多
文摘The frequency selective surface (FSS) has been widely applied by means of its spatial frequency-filter characteristic, but it is always designed and used as a device with fixed frequency response. In order to tune the resonant frequency and switch the frequency channel, a scheme of mechanically tunable FSS is theoretically analyzed by using the method of Floquet's vector modes expansion and fields matching. A double-layer tunable FSS with dipole element can perform a dynamic range of resonant frequency covering whole X-band.
基金supported by the National Natural Science Foundation of China(No.10904118)the Natural Science Foundation of Hubei Province(No.2009CDB211)the Fundamental Research Funds for the Central Universities
文摘To resolve the problem of missed evanescent waves in a beam focusing system,a hyperlens-based beam focusing device is proposed in this letter.This device can convert the evanescent waves into propagating waves,and then a super-resolution spot is formed at the center of the hyperlens.The working principle of the device is presented,and the way in which the material and structural parameters of the hyperlens affect the resolution and transmission is analyzed in detail.A multibeam focusing device is optimally designed,and the simulated results verify that a nanoscale spot with a diameter of 15.6 nm（corresponding toλ0/24,whereλ0 is the working wavelength in vacuum）is achieved,which is far less than the diffraction limited resolution with a value of 625 nm（1.7λ0）.The device is expected to find numerous applications in optical data storage and nano-photolithography,among others.
基金supported by the National Natural Science Foundation of China (No. 11504148)the Fundamental Research Funds for the Central Universities (Nos. lzujbky-2015-269 and lzujbky-2016-35)
文摘The propagation of a filamentary laser beam at an air-glass surface is studied by setting the incident angle sat- isfying the total reflection condition. The images of the trajectory of the filamentary laser beam inside the sample and the output far-field spatial profiles are measured with varying incident laser pulse energies. Different from the general total reflection, a transmitted laser beam is detected along the propagation direction of the incident laser beam. The energy ratio of the transmitted laser beam depends on the pulse energies of the incident laser beam. The background energy reservoir surrounding the filament core can break the law of total reflection at the air-glass surface, resulting in the regeneration of the transmitted laser beam.
