Wideband reflectors with zero-contrast gratings.

We present wideband resonant reflectors designed with gratings in which the grating ridges are matched to an identical material, thereby eliminating local reflections and phase changes. This critical interface thus possesses zero refractive-index contrast; hence "zero-contrast gratings." We design reflectors with zero-contrast gratings and high-contrast gratings and compare the results. For simple gratings with two-part periods, we show that zero-contrast grating reflectors outperform comparable high-contrast grating reflectors. An example silicon-on-glass reflector exhibits a 99% reflectance bandwidth of ∼700  nm for zero refractive-index contrast Δn=0, whereas a high-contrast device with Δn=2 yields a bandwidth of ∼600  nm. It follows that local Fabry-Perot modes residing in the grating ridges and reflecting off a high-contrast interface are not the root cause of wideband reflection.

[1]  Thomas K. Gaylord,et al.  Stable implementation of the rigorous coupled-wave analysis for surface-relief gratings: enhanced transmittance matrix approach , 1995 .

[2]  Y. Suzuki,et al.  Broad-band mirror (1.12-1.62 /spl mu/m) using a subwavelength grating , 2004, IEEE Photonics Technology Letters.

[3]  S Tibuleac,et al.  Narrow-linewidth bandpass filters with diffractive thin-film layers. , 2001, Optics letters.

[4]  Ivan Avrutsky,et al.  Reflection of a beam of finite size from a corrugated waveguide , 1989 .

[5]  A. A. Oliner,et al.  A New Theory of Wood’s Anomalies on Optical Gratings , 1965 .

[6]  Evgeny Popov,et al.  Zero order anomaly of dielectric coated gratings , 1985 .

[7]  Vladimir A. Sychugov,et al.  Diffraction characteristics of planar corrugated waveguides , 1986 .

[8]  R. Magnusson,et al.  Physical basis for wideband resonant reflectors. , 2008, Optics express.

[9]  Vladimir A. Sychugov,et al.  LETTERS TO THE EDITOR: Total reflection of light from a corrugated surface of a dielectric waveguide , 1985 .

[10]  G. Michael Morris,et al.  Resonant scattering from two-dimensional gratings , 1996 .

[11]  Badhise Ben Bakir,et al.  Surface addressable photonic crystal membrane resonators: generic enablers for 3D harnessing of light , 2012, Other Conferences.

[12]  P. Vincent,et al.  Corrugated dielectric waveguides: A numerical study of the second-order stop bands , 1979 .

[13]  X. Letartre,et al.  Broadband and compact 2-D photonic crystal reflectors with controllable polarization dependence , 2006, IEEE Photonics Technology Letters.

[14]  R. Magnusson,et al.  Resonant leaky-mode spectral-band engineering and device applications. , 2004, Optics express.

[15]  Robert Magnusson,et al.  Resonant wideband polarizer with single silicon layer , 2011 .

[16]  Weijian Yang,et al.  High-contrast gratings for integrated optoelectronics , 2012 .

[17]  C. Chang-Hasnain,et al.  Ultrabroadband mirror using low-index cladded subwavelength grating , 2004, IEEE Photonics Technology Letters.

[18]  Robert Magnusson,et al.  Particle swarm optimization and its application to the design of diffraction grating filters. , 2007, Optics letters.

[19]  A. Friesem,et al.  Resonant grating waveguide structures , 1997 .

[20]  S. S. Wang,et al.  Theory and applications of guided-mode resonance filters. , 1993, Applied optics.