Optimal-Design For Antireflective Tapered 2-Dimensional Subwavelength Grating Structures
Abbreviated Journal Title
J. Opt. Soc. Am. A-Opt. Image Sci. Vis.
DIFFRACTIVE OPTICS; SUBWAVELENGTH GRATINGS; EFFECTIVE-MEDIUM THEORY; GRADIENT INDEX; ANTIREFLECTION; RELIEF GRATINGS; SURFACES; Optics
Techniques for the design of continuously tapered two-dimensional (2D) subwavelength surface-relief grating structures for broadband antireflection surfaces are investigated. It has been determined that the Klopfenstein taper [Proc. IRE 44, 31 (1956)] produces the optimum graded-index profile with the smallest depth for any specified minimum reflectance. A technique is developed to design the equivalent tapered subwavelength surface-relief grating structure by use of 2D effective-medium theory. An optimal Klopfenstein tapered 2D subwavelength grating is designed to reduce the Fresnel reflections by 20 dB over a broad band from an air-substrate (n(s) = 3.0) interface. The performance is verified by use of both a 2D effective-medium-theory simulation algorithm and rigorous coupled-wave analysis. These structures are also shown to achieve this low reflectance over a wide field of view (theta(FOV) > 110 degrees). The pyramidal spatial profile, which has generally been assumed to produce the optimal broadband antireflection grating structure, is shown to require a significantly larger depth to achieve the same performance as a Klopfenstein-designed tapered antireflection grating structure.
Journal of the Optical Society of America a-Optics Image Science and Vision
"Optimal-Design For Antireflective Tapered 2-Dimensional Subwavelength Grating Structures" (1995). Faculty Bibliography 1990s. 1347.