Highly Resistant Zero‐Order Waveplates Based on All‐Silica Multilayer Coatings

Abstract

Waveplates, used to modify polarization state of light, are integral part of high‐power lasers. Classical approach to waveplate manufacturing is based on combination of birefringent crystalline materials and deposition of nonpolarizing antireflection (AR) coatings. Their limitation to withstand maximal peak power is determined by laser‐induced damage (LID) phenomena, mainly determined by low band‐gap materials used in AR coatings. In this study, a novel multi‐layer approach of high band‐gap birefringent coatings was proposed and investigated to overcome this limitation. Three eligible candidate materials, namely LaF3, Al2O3, and SiO2 are investigated. Structural and optical analysis reveal superior properties of silica for UV spectral range. Zero‐order thin film retarders based on all‐silica nano‐structures are fabricated by oblique angle deposition process. Low optical losses and high transparency (T ∼ 99%) are demonstrated while indicating potential to withstand high laser fluence of 40 J cm−2 in nanosecond regime at 355 nm wavelength. Such waveplates can essentially improve maximal tolerated peak power and thus allow production of more compact optical systems, even when high laser power is used.

Releasable Micro-waveplates

“…Columnar thin films (CTF), formed by oblique angle deposition technique, exhibited phase retardance due to the optical anisotropy [3]. The substrates were placed above the evaporation source and by manipulating it with dual stepper motors, variety of CTFs were realized ( Fig.…”

Investigating the Trade‐off between Optical and Mechanical Properties during Constrained Sintering of Mesomorphic Ceramic Films

“…While this method can result in high transparency, laser damage resistance, and precise control of retardance, it is expensive and cannot be applied uniformly over large areas. [ 9–12 ]…”

“…While this method can result in high transparency, laser damage resistance, and precise control of retardance, it is expensive and cannot be applied uniformly over large areas. [9][10][11][12] Mesomorphic ceramics are defined as inorganic solids with morphologies intermediate between isotropic materials and single crystals. Due to their optical anisotropy, mesomorphic ceramics are under consideration as alternative waveplate materials.…”

RGB‐Color Image Analysis for Determination of Birefringence of Micro‐Films and Columnar Coatings

“…[ 19,20 ] Additionally, using glancing angle deposition (GLAD) method enabled to form optical components for high power laser systems due to enhanced anisotropy in silica thin films. [ 21–23 ] Optical properties of such coatings strongly depend on deposition conditions and features of the substrate. [ 24,25 ] Therefore, flexible and high resolution method for anisotropy analysis is essential for further development of complex elements.…”