Bypassing and cutting through 1D photonic crystals by ultra-shallow wet-etched resonant gratings

The electromagnetic field in subwavelength resonant diffractive optical elements is so concentrated that a very shallow surface corrugation obtained by wet chemical micro–nano-etching is sufficient to give rise to high contrast diffraction effects allowing a high wavelength-, polarization- or transverse-mode-selectivity which is not achievable by conventional diffractive elements. Two examples of polarizing laser mirrors at both extremes of the optical spectrum with wet-etched grating bypassing and cutting through the 1D photonic crystal are demonstrated.

► Ultra-shallow grating thwart robust 1D photonic crystals.
► Highly selective sub-μm resonant gratings fabricable by wet etching.
► Optical micro–nano-structuring likes alkaline processes.
► Resonant gratings control laser emission from far-IR to deep-UV.