共查询到20条相似文献,搜索用时 515 毫秒
1.
Binfeng Yun 《Optics Communications》2011,284(1):485-489
A compact nanometric surface plasmon polariton Fabry-Perot filter based on three metal-insulator-metal (MIM) waveguides is proposed and studied. The characteristics of this SPP band pass filter are analyzed by the finite difference time domain method and the Fabry-Perot resonance model. The results show that the resonance wavelengths of the pass bands can be linearly changed by the resonant cavity length, and the transmission ratios of the pass bands can be varied by altering the gaps between the MIM waveguides. The metal loss and dispersion effects on the SPP filter's spectra are considered as well. This kind of simple filter is very promising for high density SPP waveguide integrations. 相似文献
2.
We theoretically introduce a new type of optical all-pass filter based on guided resonance in coupled photonic crystal slabs. The filter exhibits near-complete transmission for both on- and off-resonant frequencies and yet generates large resonant group delay. We further show that such a filter can be mechanically switched into a flat-top band rejection filter. 相似文献
3.
Lin Liu Xia Hao Yutang Ye Juanxiu Liu Zhenlong Chen Yuncen Song Ying Luo Jing Zhang Liang Tan 《Optics Communications》2012,285(10-11):2558-2562
A nanometric surface plasmon polariton (SPP) filter based on a vertical coupled metal–insulator–metal (MIM) Fabry–Perot resonator is proposed and analyzed. The transmission characteristics of the SPP filter are analyzed in detail by using the finite difference time domain method. And the resonance condition derived by the numerical method is consonant with the analytic model based on the Fabry–Perot model, which includes the metal loss and dispersion effects. And the simulation results show that multiple transmission dips can be formed and the resonance wavelengths of the transmission dips can be altered by the Fabry–Perot cavity length and width. Also the extinction ratio and the quality factor of the filter are affected by the barrier thickness of the coupling region. The proposed nanometric plasmonic filter is simple and very promising for the SPP waveguides platform. 相似文献
4.
U. Strom 《Solid State Ionics》1983,8(4):255-279
Experimental and theoretical results are reviewed relevant to the conduction plane disorder in the nonstoichiometric fast ion conductor Naβ-alumina. Thermal, dielectric, acoustic, nuclear magnetic resonance and electron spin resonance measurements at low temperatures (<50 K) can be interpreted in terms of the tunneling mode formalism previously proposed for glasses. Experimental results at higher temperatures exhibit behavior similar to glasses near their glass transition. 相似文献
5.
6.
7.
A notch filter using a different grating scheme is investigated theoretically. The grating is the thermo-optic index change induced by individually controllable heaters that are periodically arranged on the filter surface. If the index change pattern induced by the heaters is in the form of sampling a periodic index change, the transmission spectrum of the filter has the same resonance band as that generated by the periodic index change. Simulation results show that the attenuation, bandwidth, and center wavelength of a resonance band are independently adjustable. In addition, it is shown that the transmission spectrum may be tailored to arbitrary predictable shapes. Finally, the realization of the filter is discussed. 相似文献
8.
For daytime operation a new receiver for potassium resonance temperature lidars was developed that includes a twin Faraday anomalous dispersion optical filter and a high-performance photon-counting avalanche photodiode instead of a photomultiplier. The design of a flat spectral filter shape over the lidar scan range avoids instrumental error on the temperature results. Initial temperature measurements under daylight conditions were realized. 相似文献
9.
In this paper, four optical filter topologies based on metal–insulator–metal waveguides are proposed and the designed structures are investigated numerically using finite-difference timedomain method. Triangular-shaped adjunctions have been added to the filter structures to improve their transmission spectrum. These improved structures consist of air as the insulator and silver as the metal. The relative permittivity of metal has been described via the Drude,Drude–Lorentz, and Palik models. The first filter's transmission spectrum shows an acceptable transmittance. In the second optimized filter, the transmission spectrum has been improved. The transmittance spectrum can be tuned through adjusting the edge of the triangle in these four optimized filters. As a result, the bandwidths of resonance spectra can be adjusted. The theory of such tapered structures will be investigated by the tapered transmission line and will be solved with the transfer matrix method. This method shows a better performance and higher transmission efficiency in comparison with the basic structures. On the other hand, the final filter has been chosen as the best one because of its hexagonal resonator. The main reason for having a better result is due to a longer interaction length in comparison with the circular resonator. This in turn creates much better energy coupling and results in higher transmission. 相似文献
10.
11.
In this paper, a novel guided-mode resonances (GMRs) based embedded dual-wavelength filter, which had the bilayer gratings located at the two sides of dielectric substrate and arranged at asymmetric position, was investigated and studied theoretically. As compared to symmetric structures that usually provided single wavelength of transmission resonance, as one normal incidence was used for transverse magnetic polarized light, the designed asymmetric structure could generate two remarkable narrow band wavelengths of transmission resonance. The parameters to affect the resonance wavelengths and the transmission resonance Q value (Q = λ/Δλ) of two bands were the distance between the two metallic gratings, the relatively lateral positions of the upper and lower gratings, the number of structure period, the thicknesses of metallic gratings, and the thickness of dielectric film. By optimizing the designed parameters, a GMR device with two resonance wavelengths located at 1239 and 1302 nm showed relative optimal performance because they had high transmission depth (99.9% and 90%) and ultra-narrow transmission bandwidth (2.8 and 1.8 nm) at the two resonance wavelengths. The presented structure can offer a potential route towards dual-band narrow-band filters and refractive index sensors in the near infrared. 相似文献
12.
提出了由十字连通形环形谐振腔耦合两个金属-介质-金属(metal-insulator-metal, MIM)波导的结构,并用有限元法数值研究了表面等离极化激元在结构中的传输特性.通过对透射谱的研究,系统地分析了MIM结构的传感特性.结果表明,在透射光谱中有三个共振峰,即存在三种共振模式,其中透射峰与材料的折射率呈线性关系.通过对结构参数的优化,得到了折射率灵敏度(S)高达1500 nm/RIU的理论值,相应的传感分辨率为1.33×10~(-4)RIU.更重要的是,灵敏度不受结构参数变化的影响,这意味着传感器的灵敏度不受制造偏差的影响.此外,谐振波长与环形腔中心半径成线性关系,该器件在较大波长范围内实现可调谐带通滤波.透射强度随着波导与环形腔间距的增大而减小,透射带宽同时减小,因此,可以通过控制环形腔与波导的耦合距离来调谐透射强度及透射带宽.研究结果对高灵敏度纳米级折射率传感器和带通滤波器的设计以及在生物传感器方面的应用都具有一定的指导意义. 相似文献
13.
基于开口谐振环结构设计了多频带太赫兹波调制器,并在谐振环的开口处及两侧均填充温敏介质锑化铟(InSb),研究了锑化铟的电磁性质随温度的变化、等效电感的组数对共振频带数目的影响以及锑化铟不同的填充方式对太赫兹波调制特性随温度的变化规律。研究结果表明,当环境温度从160 K上升到350 K时,锑化铟的载流子浓度和等离子体频率逐渐增大,然而等效介电常数却不断减小;每增加一组等效电感,太赫兹波调制器都会相应的增加一个共振频带;在调制器开口处和两侧均填充锑化铟时,当环境温度在160~350 K变化时,温度对太赫兹波的共振频率和共振幅度的调制效果比仅在开口处或者两侧填充锑化铟时更明显,且随着温度的升高,每个共振频带所对应的共振频率均明显增大。 相似文献
14.
We report the experimental demonstration of an ultranarrow bandwidth atomic filter by optically induced polarization rotation in multilevel electromagnetically induced transparency systems in hot Rb vapor. With a coupling intensity of 2.3 W/cm^2, the filter shows a peak transmission of 33.2% and a bandwidth of 10 MHz. By altering the coupling frequency, a broad tuning range of several Doppler linewidths of the D1 line transitions of STRb atoms can be obtained. The presented atomic filter has useful features of ultranarrow bandwidth, and the operating frequency can be tuned resonance with the atomic transition. Such narrowband tunable atomic filter can be used as an efficient noise rejection tool in classical and quantum optical applications. 相似文献
15.
We report what is believed to be the first demonstration of measurement of tropospheric temperature profiles in daytime by use of a high-spectral-resolution Rayleigh-Mie lidar at an eye-safe wavelength of 355 nm. Atmospheric temperature is determined from the linewidth of the Rayleigh spectrum. Two Rayleigh signals are detected with Fabry-Perot etalon filters with a dual-pass optical layout. The Mie signal is detected with a third etalon filter for correcting the Mie component in the Rayleigh signals. The temperature statistical uncertainties are below 1 K up to a height of 3 km in nighttime and 2 km in daytime with a relatively compact system that uses laser energy of 180 mJ and a 25-cm telescope. Good agreement between lidar and radiosonde measurements is obtained. 相似文献
16.
17.
A theoretical analysis of nano-deep corrugated long-period waveguide gratings on a SU-8 polymer-based channel waveguide with NOA61 optical epoxy coated upper- and lower cladding is presented. The transmission spectra of the gratings show strong rejection bands both at visible (at wavelength region of 450?460 nm) and infra-red (at wavelength region of 1530?1540 nm) regions when a grating period of ?68 μm with optimized grating tooth height is considered. Phase-matching graphs are studied to find the relationship between resonance wavelength and grating period. These results show that the grating parameters significantly affect the characteristics of transmission spectra as well as the resonance wavelength of the grating. Long-period waveguide grating-based band pass filter made by use of same polymer materials are also designed and analyzed. These types of waveguide grating-based filters can widely be used for visible and infra-red wavelength sensing applications. 相似文献
18.
Diamagnetic muon spin resonance experiments were carried out in a-quartz at two temperatures: 300 K and 130 K. A strong diamagnetic resonance peak was observed at both temperatures. The spectrum exhibits an anisotropy in the chemical shift of 15 ppm (300K) and 25 ppm (130K). 相似文献
19.
20.
C. Wood J. Cunningham I. C. Hunter P. Tosch E. H. Linfield A. G. Davies 《International Journal of Infrared and Millimeter Waves》2006,27(4):557-569
The generation and detection of guided wave terahertz (THz) transients in microstrip transmission line systems is demonstrated
at both room and cryogenic (∼ 4 K) temperatures using thin film low-temperature-grown GaAs (LT-GaAs) switches, excited by
a 100 fs, 80 MHz repetition rate pulsed Ti:Sapphire laser. The characterisation of passive filter elements formed in the microstrip
line is reported, together with their response to the application of dielectric loads of varying thickness at room temperature. 相似文献