CHARACTERISTICS OF OPTICAL GUIDED-MODE RESONANCE FILTERS

本基金旨在研究波导几何中周期性介电结构的导模共振特性。理论工作表明，这种结构可以作为有效的开关和任意窄带无损滤波器。提出了理论和实验工作。本文将采用严格耦合波理论详细研究体光栅和面光栅的导模共振特性。谐振特性将与光学波长、光栅厚度、入射角、光栅周期、体介电常数、入射波偏振和介电常数调制幅度有关。将考虑多介质层几何形状，并将导模谐振滤波器的性能与经典的法布里-佩罗滤波器进行比较。这一理论将经过实验检验。为此，体光栅滤光片将被全息记录在玻璃和石英衬底上的重铬化明胶波导薄膜中。表面浮雕光栅滤波器将在钆镓石榴石衬底上的钇铁石榴石波导中生产。动态的、可旋转的滤光片将由光折变晶体（GaAs）薄膜中的激光诱导光栅产生。这项研究的意义在于解释了与衍射结构有关的新的基本现象。这项工作的许多有用的应用可以预见，包括激光腔滤波器，窄线镜，可调谐滤波器，电光开关和增强薄膜设计。

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.