Design of single-material guided-mode resonance filter

In this letter, a guided-mode resonance （GMR） filter with the same material for both the grating layer and the waveguide layer is designed, and its optical properties are investigated. The GMR filter owns almost 100% reflection at the resonance wavelength of 800 nm with the full-width at half-maximum （FWHM） of 20 nm, and its sideband reflection from 700 to 1000 nm is less than 5%. As the resonance wavelength is influenced by more than one parameter during the fabrication process, GMR filter with the same resonance wavelength can be obtained by adjusting other parameters or even one parameter to deviate from the design value.     

High-efficiency guided-mode resonance filter

A high-efficiency guided-mode resonance reflection filter is reported. The device consists of a surface-relief photoresist grating and an underlying HfO (2) waveguide layer deposited on a fused-silica substrate. The spectral response measured with a dye-laser beam at normal incidence exhibited a peak reflectance of 98% at a wavelength of 860 nm with sideband reflectance below ~5% extending over the wavelength range provided by the dye (800-900 nm). At normal incidence the filter linewidth was 2.2 nm. High-efficiency double-peak resonances occurred at nonnormal incidence, with the spectral locations of the maxima vayring with the incidence angle. The filter response at various angles of incidence agreed well with the theoretically calculated reflectance curves.     

Guided-mode resonance Brewster filter

A new type of optical filter is predicted theoretically and verified experimentally. The filter operates under guided-mode resonance conditions in a thin-film waveguide grating. A high-efficiency reflection filter response is produced at the Brewster angle at which TM reflection is classically prohibited. Low-reflectance sidebands are obtained that are adjacent to the resonance peak induced by the Brewster effect in the neighborhood of the resonance peak. A double-layer waveguide grating yields 94% experimental reflectance at the thin-film Brewster angle for a Gaussian laser beam with TM polarization at the 1064-nm wavelength.     

Colored image produced with guided-mode resonance filter array

A method to reproduce colored images with a guided-mode resonance filter (GMRF) array is presented in this Letter. Because of their excellent characteristics, monochromatic light of the three primary colors with high purity can be achieved by using GMRF structures. Moreover, the primary colors are obtained without changing other GMRF parameters except the period, which could be realized easily with laser direct writing technology. The result shows that a colored image with high resolution and verisimilitude can be reproduced.     

Nonpolarizing and tunable perpendicular dual-grating guided-mode resonance filter

A perpendicular dual-grating (PDG) guided-mode resonance filter was constructed by placing two identical waveguide gratings close to and their grooves perpendicular to each other. Multilayer waveguide theory was used to estimate the resonant wavelength for the TE and TM polarization incidences, and the rigorous coupled wave analysis (RCWA) was used to investigate the resonant wavelength, the lineshape and linewidth of the resonant peaks for arbitrary polarization incidences. The filter presents identical spectral characteristics for normally incident wave with arbitrary polarization. The separation of the resonant reflection peaks corresponding to the TE₀ and TM₀ split modes were realized by properly selecting the geometrical and material parameters of the grating layers and the waveguide layers. Measurement of the nano air gap between 0 and 0.4 p by determining one of the two resonant reflection peaks of the TE₀/TM₀ split modes was achieved without being interfered by the TM₀/TE₀ split modes.     

Polarization-independent guided-mode resonance filter with cross-integrated waveguide resonators

A cavity-resonator-integrated guided-mode resonance filter (CRIGF) has been proposed and investigated in order to realize high-efficiency narrowband reflection with a small aperture. The CRIGF consists of a grating coupler integrated in a cavity resonator constructed by a pair of distributed Bragg reflectors on a thin-film waveguide. This time, orthogonally crossed integration of two CRIGFs was demonstrated in order to obtain polarization-independent reflection spectrum. An SiO₂-based device with 10?μm aperture was designed and fabricated for around 850?nm wavelength operation, and narrowband polarization-independent reflection was confirmed experimentally.     

Tunable guided-mode resonance filter based on dielectric elastomer actuators

A tunable guided-mode resonant (GMR) reflection filter based on dielectric elastomer actuators (DEA) is designed. Simulating the characteristics of the filter with rigorous coupled wave analysis, it is shown that the resonant wavelength of the kind of GMR filter can be tuned from 1442.8 nm to 1644.6 nm by applying voltage on the dielectric elastomer actuators which changes the period of the grating layer of the GMR filter conveniently. Furthermore, there is an almost perfect linear relationship of resonant wavelength tuned and the period varied with negligible effect on the linewidth.     

带虚设层的抗反射结构导模共振滤波器设计与分析

提出带虚设层的抗反射导模共振滤波器结构及设计方法,该方法适用于任意角度入射带虚设层的抗反射结构导模共振滤波器设计与分析.得到带虚设层的导模共振滤波器抗反射结构所满足的关系式.指出在维持虚设层光学厚度不变的情况下,可以通过不同选材,在低反射旁带中实现等带宽不同波长的选择.此外,由于结构的抗反射特性在低角范围内具有较大的角度容差,改变入射角,可以实现滤波波长及光谱带宽在宽光谱范围内的准线性可调谐.     

Single-material guided-mode resonance filter for TE waves under normal incidence

<正>A guided-mode resonance(GMR) filter with the same material(Ta_2O_5) for both the grating layer and the waveguide layer is designed and fabricated.This simple structure is easy to fabricate and can avoid the defects at the grating/waveguide interface using different materials.The spectral response measured with a Lambda 900 spectrophotometer under normal incidence for TE waves exhibits a peak reflectance exceeding 80%at the wavelength of 1040 nm with a full-width half-maximum(FWHM) linewidth of 23 nm.We evaluate the deviations of the fabricated structure from the designed parameters.     

Tunable intensity of the spectral reflectance of a guided-mode resonance filter with dual channels

Simulating the characteristics of a guided-mode resonance filter with rigorous coupled wave analysis, we find that, by adjusting the azimuthal angle of the grating used as a sub-layer of the guided-mode resonance filter from 0° to 90° under TE-reflectance, the intensity of the spectral reflectance of the guided-mode resonance filter monotonically increases at the wavelength of 684.6 nm, while the spectral reflectance monotonically decreases at the wavelength of 723 nm. Moreover, the spectral reflectance with TE-reflectance at 90° corresponds to the TM-reflectance at 0°. The phenomenon means that the intensity of the spectral reflectance can be easily tuned with different azimuthal angles by choosing appropriate structure parameters of the guided-mode resonance filter.     

Optimization of a guided-mode resonance filter by varying the thickness of the buffer layer

In this Letter, we demonstrate that by adjusting the thickness of the buffer layer, the optical responses of a guided-mode resonance filter(GMRF) can be improved for sensor applications. The GMRF is fabricated using a replica molding with a plastic substrate and a UV-curable polymer. SiO_2 buffer layers of different thicknesses are deposited before the waveguide-layer deposition. The sensitivity of the GMRFs decreases slightly with increasing SiO_2 layer thickness. By contrast, the full width at half-maximum reduces substantially with increasing SiO_2 layer thickness, resulting in the improvement of the overall figure of merit.     

Numerical analysis of a dual-wave band guided-mode resonance filter with embedded bilayer asymmetric metallic gratings

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.     

Design of guided-mode resonance filters with an antireflective surface at oblique incidence

A design approach of guided-mode resonance filter (GMRF) with an antireflective surface at oblique incidence is presented. For a given incident angle or grating filling factor, the required grating filling factor or incident angle can be expressed by the analytical forms of the quadratic equations at quarter-wavelength thickness. Long-range, low sidebands are obtainable for a single-layer GMRF under the TM mode wave illumination at oblique incidence. The reflection properties such as the symmetry of the lineshape and the sideband level in the logarithm scale can be further improved by slightly varying both the grating period and the grating thickness. Magnetic field enhancement occurs in these structures due to the coupling between the evanescent diffracted order and the waveguide mode.     

Multidimensional angle sensing method using guided-mode resonance

Optical Review - A waveguide grating on a transparent substrate can serve as an optical notch filter owing to guided-mode resonance. The filtering wavelength is highly sensitive to an incidence...     

Pressure-tunable guided-mode resonance sensor for single-wavelength characterization

A method of tuning a one-dimensional guided-mode resonance grating through the use of an air-pressure-responsive membrane is demonstrated here using finite-element method simulation. The device consists of a titanium dioxide (TiO(2)) grating structure embedded in a flexible polydimethylsiloxane membrane. This grating has a resonant response to TM-polarized light at a wavelength dependent upon the refractive index of the surrounding medium. By varying the pressure by 5500 Pa, lateral strain may be applied to the grating; this allows resonances to be produced for medium refractive indices ranging from 1.33 to 1.50 for a fixed-wavelength 850 nm light source.     

Electric field enhancement in guided-mode resonance filters

Electric fields inside guided-mode resonance filters (GMRFs) may be intensified by resonance effects. The electric field enhancement is investigated in two GMRFs: one is resonant at normal incidence, the other at oblique incidence. It is shown that the two GMRFs exhibit different behaviors in their electric enhancement. Differences between the electric field distributions of the two GMRFs arise because coupling between counterpropagating modes occurs in the first case. It is also shown that the order of the electric field of maximum amplitude can be controlled by modulation of the dielectric constant of the grating.     

Single-layer one-dimensional nonpolarizing guided-mode resonance filters under normal incidence

We demonstrate that properly designed one-dimensional guided-mode resonance filters (GMRFs) with only one grating layer can exhibit a nonpolarizing resonant filtering effect under normal incidence. A sinusoidal profile nonpolarizing GMRF is realized by photoinduced surface-relief grating formation on thin films of polymer-azobenzene complexes and subsequent atomic layer deposition, showing the feasibility of fabrication of such compact GMRFs.     

介质光栅导模共振耦合波分析

导模共振是由于光栅介质内高级次子波耦合进光栅所支持的泄漏模中,导致传播波能量重新分布的结果.采用严格的耦合波方法,通过分析波导的导波模式,正确估计出弱调制介质光栅导模共振的位置.并对导模共振与光栅厚度、基底厚度以及入射角的关系作了讨论.通过采用抗反射设计,获得了具有对称、低旁带特点的窄带共振峰 关键词： 导模共振 耦合波     

Optimizing the quality factor of a wideband guided-mode resonance biosensor

This work studies the effect of the biochemical molecular layer on the quality factor of guided-mode resonance (GMR) filter of an ultrasensitive label-free biosensor. A GMR biosensor with a narrower bandwidth has a higher sensitivity but requires much higher accuracy in its fabrication process. In this study, we have managed to present a GMR filter with a narrow bandwidth that requires less precision by controlling the thickness of the biochemical molecule layer, which increases the Q factor by up to three times.     

Transmission guided-mode resonance filters based on high reflection multilayer stacks

The transmission guided-mode resonance filters are implemented by integration of diffraction grating into classical thin films to produce high efficiency in the central wavelength and arbitrarily low sideband response over a quite large spectral range. Transmission guided-mode resonance filters require considerable fewer thin films to acquire narrow line width and high peak transmission in the central wavelength compared with classical multilayer high-reflectance coatings with a stack of quarter-wave thickness. The properties of transmission filters with single/double waveguide grating in the different layers of high refection stacks are compared each other. It is demonstrated that the narrow line width transmission filters can be abstained with only two different materials.