Optical Gradient Waveguides in Photo-Thermo-Refractive Glass Formed by Ion Exchange Method

Abstract

Photo-thermo-refractive (PTR) glasses are the class of polyfunctional materials that combine the properties of several monofunctional materials such as photo-refractive, laser, luminescent, and plasmonic ones. Based on PTR glasses, various diffractive holographic elements and photonic devices were developed in both the volume and fiber versions. In this paper, the fabrication of optical planar waveguides on PTR glass by low-temperature ion exchange is reported for the first time. Planar waveguides were fabricated through substituting the sodium ions in glass by silver, potassium, rubidium, and cesium ones from the nitrate melts. The silver waveguides were shown to have the largest depth (27 μm) and reveal no birefringence. For the silver waveguides, an increase in the refractive index is caused by differences in the polarizabilities of cations exchanged. The maximum increment of the refractive index was observed in the cesium waveguides (0.0512). An increase in the refractive index and also appearing the birefringence in potassium, rubidium, and cesium waveguides are found to be due to the compressive mechanical stresses and their relaxation. The potentialities of the ion exchange technology for fabricating, in PTR glasses, planar gradient waveguides with low losses (0.5 dB/cm) are demonstrated, the potentialities extending the application field of PTR glasses in photonics.Index Terms-Ion exchange, optical waveguides, photo-thermorefractive glass. 0733-8724

Governing Functionality of Silver Ion-Exchanged Photo-Thermo-Refractive Glass Matrix by Small Additives

“…Currently, phase holograms recorded in PTR glass are used as line-narrowing and stabilizing filters, spectral and spatial filters, compressors for femtoand picoseconds laser beams, spectral beam combiners, high-power beam splitters, etc. Although PTR glass was developed as a photosensitive medium for recording volume Bragg gratings, recent studies showed that it is a polyfunctional material that can combine the properties of holographic, laser, and photoetchable media [1,2,[5][6][7][8]. In this work, we demonstrate that the functionality of PTR glass matrix can be substantially extended via the formation of silver nanostructures inside the glass or on its surface.…”

Голографические Оптические Компоненты На Основе Фоторефрактивных Кристаллов И Стекол: Сранительный Анализ И Перспективы Развития

“…на лазерных ФТР стеклах, активированных неодимом, эрбием и иттербием, получена генерация, что открывает возможности реализации в стекле идеологии монолитной интеграции брэгговских решеток и лазерной среды, по аналогии с полупроводниковыми лазерами с распределенной обратной связью [19,20].…”

“…Так, ФТР стекла содержат щелочную компоненту (ионы натрия), и к таким стеклам применима ионообменная технология, например, возможно заменять ионы натрия в ФТР стекле на ионы серебра, калия, рубидия, цезия из внешнего источника -расплава соли. Эта технология позволяет повышать показатель преломления ( n = 10 −3 ) на поверхности ФТР стекла и создавать ионообменные оптические Ag + , K + , Rb + и Cs + волноводы, а также упрочнять поверхность за счет сжимающих диффузионных напряжений[19].…”

Features of Volume Holograms in Fluoride and Chloride Photothermorefractive Glass

“…These ions can be changed on another monovalent ion (silver, potassium, rubidium, and cesium) by a well-known ion-exchange technique. This approach allowed us to fabricate ion-exchanged optical, luminescent, and plasmonic waveguides as well as to increase the mechanical, thermal, and optical resistance of the glass [20].…”