The phenomenon of resonant reflection from a grating-coupled waveguide mode is conceptually, technologically, and experimentally transposed from a planar corrugated waveguide structure under plane wave excitation to a circularly symmetrical waveguide at the inner wall of a tube under cylindrical wave excitation. The mode coupling element is an azimuthally periodic wall corrugation having an integer number of lines parallel to the tube axis. The grating is defined by diffractive coordinate transform of a radial grating phase-mask transverse to the tube axis under axial beam exposure onto a photoresist-coated TiO2 sol-gel wall-waveguide. The holistic excitation of a waveguide mode is achieved by transforming a broad spectrum, centered axial incident beam into a cylindrical wave by a centered, 90° apex reflective cone. The expected resonantly reflected cylindrical wave at the mode-coupling wavelength is in turn transformed back into an axial beam by the cone. TE resonant reflection is demonstrated experimentally.

中文翻译：

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整体激励下圆柱形光栅波导的共振反射

光栅耦合波导模式的共振反射现象在概念上、技术上和实验上从平面波激励下的平面波纹波导结构转换到圆柱波激励下管内壁的圆形对称波导。模式耦合元件是具有整数条平行于管轴的线的方位角周期性壁波纹。光栅由径向光栅相位掩模在轴向光束曝光下横向于管轴的衍射坐标变换定义到光刻胶涂层的 TiO2 溶胶-凝胶壁波导上。波导模式的整体激发是通过将宽光谱、居中的轴向入射光束通过居中的 90° 顶点反射锥转换为圆柱波来实现的。在模式耦合波长下预期的共振反射柱面波又被锥体转换回轴向光束。TE 共振反射是通过实验证明的。