Spectral resolution analysis of resonant grating waveguides

A high spectral resolution analysis of narrowband reflection filters based on resonant grating waveguide structures is presented. A tunable high‐performance dye laser with ～0.15 cm^‐1 line width and a beam analyzing system consisting of three simultaneously controlled CCD cameras were used to investigate grating waveguide resonances at wavelengths ～694 nm and ～633 nm. A reflectivity of 91 % and a line width of ～0.3 nm were measured and theoretically modeled for a resonant reflection filter specifically designed for the ruby laser wavelength 694.2 nm. A resonance shift of several nanometers was observed for a second grating waveguide structure in the region of the helium‐neon laser emission wavelength 632.8 nm by changing the sample temperature. We discuss the potential of grating waveguide devices combining the narrow line width and the tunability of the resonant response as promising candidates for implementation in innovative concepts for reflection filter and sensor applications.