Investigation of nanoscale etching and poling of lithium niobate

Abstract

The capabilities of some nonlinear optical devices can be improved through approaches such as nano-optics. Two methods, in particular, that can enhance the wavelength conversion efficiency and versatility of current second harmonic generation (SHG) devices are creating nanoscale domain inversions (to make for efficient quasi-phase matched SHG devices at various wavelengths) and gratings in lithium niobate (to potentially achieve exact-phase matching). This thesis explores these options, creating nanoscale domain inversions and nanostructuring lithium niobate, in order to enhance current SHG devices. First, an in-depth literature survey is provided detailing the current research regarding structuring lithium niobate. Next, a description and analysis of the inductively coupled plasma reactive ion etch (ICP-RIE) etching procedures used are provided, followed by a discussion of the poling of lithium niobate using an all optical poling technique. Suggestions for continued development are presented based on the successes and failures of the procedures used for this work. The goal of this thesis is to show that lithium niobate can be nanostructured using ICP-RIE etching techniques and optical poling methods. This goal is a foundation towards the long-term goal of building more efficient nonlinear optical devices. Nanostructuring lithium niobate suggests that improved nonlinear optical devices can be made in the future, by means of nanoscale domain inversions for quasi-phase matching or nanoengineered gratings intended for exact-phase matching.