An image projection device receives a light emitted from a light source through an illumination optic for projecting to a spatial light modulator (SLM) having a plurality of deflectable micromirrors The micromirrors further formed with a sub-wavelength microstructure on a reflective surface of the micromirrors having a reflection guided mode resonant grating to take advantage of an ultra-fine processing technology available in recent years used in semiconductor manufacture and micro-machining to fabricate a sub-wavelength grating (SWG) having a pitch between the grating ridges that is smaller than the wavelength of light.