Impact of Stripe Shape on the Reflectivity of Monolithic High Contrast Gratings

Monolithic high contrast gratings (MHCGs) composed of a one-dimensional grating patterned in monolithic layer provide up to 100% optical power reflectance and can be fabricated almost any semiconductor dielectric material used modern optoelectronics. MHCGs enable integration, polarization selectivity, versatile phase tuning. They from 10 20 times thinner than distributed Bragg reflectors. The subwavelength dimensions significantly reduce the possibility ensuring smoothness sidewalls MHCG stripes make precise control shape stripe cross-section difficult during etching process. question is then whether it more beneficial improve methods obtain perfect shape, as assumed by design, or possible find geometrical parameters that using given method provides. Here, we present numerical study supported experimental characterization various materials variety common surface nanometer-scale shaping methods. We demonstrate with an arbitrary nearly 100%, which greatly relaxes their fabrication requirements. Moreover, show exceeding 99% record spectral bandwidth 20% achieved for quasi-trapezoidal cross-sections MHCGs. also sidewall corrugations have only slight impact on if amplitude corrugation less 16% period. This level precision most current Our results are significant design production photonic devices employing flexibility regard facilitates reliable highly reflective mirrors. turn will manufacture monolithically integrated high-quality-factor micro- nanocavity devices.