Optical and THz Galois diffusers

Abstract

Binary surface reliefs with sub-wavelength features making up a pseudorandom pattern based on mathematical Galois fields GF(p m) [1, 2] can scatter incoming waves into a large number of diffraction maxima within a huge solid angle. A one-dimensional (1D) Galois number sequence can be folded into a two-dimensional (2D) array by the sino-representation [2]. This concept was been verified for acoustic waves a long time ago [3, 4] and is investigated here for visible light and THz waves. Our Galois diffusers are designed as reflection reliefs and realised by electron beam lithography for the optical regime and UV photolithography for the THz regime. Our results show that optical and THz Galois surfaces are excellent diffusers for electromagnetic waves; they distribute the reflected intensity evenly over a large number of maxima nearly within the entire half solid angle in the backward direction.

Devitrite-Based Optical Diffusers

“…8 Depending on their application and working principle optical diffuse can diffuse light in one 8 or two dimensions. 13 Generally, holographic diffusers are used to achieve two dimensional diffusion of light with the desired patterns or beam widths. 14 These diffusers are mostly produced using sophisticated and expensive nanofabrication methods for patterning the surfaces which cause the optical diffusion.…”

“…Depending on their application and working principle, optical diffusion can diffuse light in one or two dimensions . Generally, holographic diffusers are used to achieve two-dimensional diffusion of light with the desired patterns or beam widths .…”

“…14 These diffusers are mostly produced using sophisticated and expensive nanofabrication methods for patterning the surfaces which cause the optical diffusion. 10,13 By comparison, devitrite is an economical material which can be produced at a much larger scale by the simple process of heat treating (devitrifying) sodaÀ limeÀsilica glass. The devitrite-based diffusers will have an advantage when producing two-dimensional diffusion patterns for light with, in addition, a degree of control over the beam width produced.…”

Theory, simulation, fabrication, and characterization of Galois scattering plates for the optical and the THz spectral range

“…[9][10][11][12][13] On the other hand, they can be regular and lithographically structured using an etch mask. 2,[14][15][16][17] In Refs. 14-16 as well as partially in Refs.…”

Nanosecond pulsed laser texturing of optical diffusers

“…19 Optical diffusers can spread light in one or two dimensions depending on their applications. 20 In this research, we report the fabrication of optical diffusers by using nanosecond laser induced surface texturing. This method differs from other techniques used for producing holographic diffusers, where a pulsed laser is used for patterning a photopolymer layer coated onto a plastic or glass substrate.…”