A new approach for broad-band omnidirectional antireflection coatings

S Dutta Gupta,G S Agarwal

doi:10.1364/oe.15.009614

Abstract

It is shown that broad-band antireflection coatings with extra large angular range can be designed based on the concept of reflectionless potentials. Numerical calculations for inhomogeneous films with or without substrate demonstrate the above capabilities for both TE and TM polarizations. The design possibilities are infinite and the underlying concept does not rely on standard use of quarter wave plates. Suitable inhomogeneous layers on both sides of a lossless thin dielectric film can thus render it invisible.

Highlights

It is well understood that any inhomogeneity in an otherwise homogeneous medium can cause reflection
It depends on the polarization of the incident light, the angle of incidence, the dielectric constants of the media and the wavelength of light, since the optical properties may depend on the wavelength
It is often a must for optical instrumentation to suppress reflection at the many interfaces of the optical components in order to increase the light throughput. This is achieved by λ /4 antireflection coatings with refractive index intermediate between those of the medium of incidence and the substrate

Summary

Introduction

It is well understood that any inhomogeneity in an otherwise homogeneous medium can cause reflection. It is often a must for optical instrumentation to suppress reflection at the many interfaces of the optical components in order to increase the light throughput This is achieved by λ /4 antireflection coatings with refractive index intermediate between those of the medium of incidence and the substrate. We show that realistic index profiles based on the reflectionless potentials can lead to almost-omnidirectional antireflection coatings with extremely large ranges of wavelength for both TE and TM polarizations. We found that the dielectric function profiles based on reflectionless potentials can offer flat response almost with total transmission over large angle and wavelength regions. We briefly outline the scheme to construct the reflectionless potentials [6] and the corresponding refractive index profiles (see Eq(6)). Where ns and ns are the refractive indices of the bounding media on the left and right of the inhomogeneous medium, respectively

Numerical results and discussions

Conclusions