CHARACTERISTICS OF OPTICAL GUIDED-MODE RESONANCE FILTERS

这项资助是为了研究波导几何中周期介质结构的导模共振特性。理论工作表明，这种结构可以作为高效开关和任意窄带无损滤光片。提出了理论和实验两方面的工作。严格的耦合波理论将被用来详细地研究体和表面浮雕光栅结构的导模共振特性。共振将根据光学波长、光栅厚度、入射角、光栅周期、体介电常数、入射波偏振和介电调制幅度来表征。我们将考虑多个介质层的几何结构，并将导模共振滤波器的性能与传统的、完全不同的法布里-珀罗滤波器进行比较。这一理论将得到实验检验。为此，体栅滤光片将被全息记录在玻璃和石英基板上的重铬酸盐明胶波导膜中。表面浮雕光栅滤光片将在镓基镓石榴石基片上，用钇铁石榴石波导制作。利用光折变晶体(GaAs)薄膜中的激光诱导光栅将产生动态的、可旋转的滤光片。这项研究的意义在于解释了与衍射结构相关的新的基本现象。这项工作可以预见到许多有用的应用，包括激光腔滤光器、窄线镜、可调谐滤光器、电光开关和增强的薄膜设计。

This grant is to study the guided-mode resonance properties of periodic dielectric structures in waveguide geometry. Theoretical work indicates that such structures can function as efficient switches and as arbitrarily narrow-band lossless filters. Both theoretical and experimental work is proposed. The rigorous coupled- wave theory will be used to study the guided-mode resonance properties of both bulk and surface-relief grating structures in detail. The resonances will be characterized with respect to the optical wavelength, grating thickness, angle of incidence, grating period, bulk permittivity, incident-wave polarization and permittivity modulation amplitude. Multiple dielectric layer geometries will be considered and the performance of the guided-mode resonance filters will be compared with the classical, fundamentally different, Fabry- Perot filters. The theory will be experimentally tested. For this, bulk- grating filters will be holographically recorded in a dichromated gelatin waveguide film on glass and quartz substrates. Surface-relief grating filters will be produced in yttrium iron garnet waveguides on gadolinium gallium garnet substrates. Dynamic, turnable filters will be produced by laser-inducing gratings in photorefractive crystal (GaAs) films. The significance of the research is that new, fundamental phenomena associated with diffractive structures are being explained. Many useful applications of this work can be envisioned, including laser cavity filters, narrow-line mirrors, tunable filters, electro- optic switches, and enhanced thin-film designs.