A new design of shallow-etched multilayer dielectric grating (MDG) exhibiting a diffraction efficiency (DE) of approximately 100% in the –1st order at 1064-nm wavelength in Littrow mounting is reported. Particle swarm optimization algorithm and Fourier modal method are used to design MDG and calculate the DE of MDG. The thickness of the grating layer is less than 80 nm which is much shallower than that in the currently reported MDG design for a high DE, which is greatly helpful for the MDG etching process. Meanwhile, the bandwidth of DE which is more than 97.5% of MDG is 60 nm, and it is a meaningful result for MDG to be used in ultrashort pulse compression system.

A guided-mode resonance (GMR) filter with the same material (Ta2O5) 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.