Quantifying the refractive index of ferroelectric domain walls in periodically poled LiNbO3 single crystals by polarization-sensitive optical coherence tomography

Research output: Contribution to journalResearch articleContributedpeer-review

Abstract

Domain walls (DWs) in ferroelectric (FE) and multiferroic materials possess an ever-growing potential as integrated functional elements, for instance in optoelectronic nanodevices. Mandatory, however, is the profound knowledge of the local-scale electronic and optical properties, especially at DWs that are still incompletely characterized to date. Here, we quantify the refractive index of individual FE DWs in periodically-poled LiNbO3 (PPLN) single crystals. When applying polarization-sensitive optical coherence tomography (PS-OCT) at 1300 nm using circular light polarization, we are able to probe the relevant electro-optical properties close to and at the DWs, including also their ordinary and extraordinary contributions. When comparing to numerical calculations, we conclude that the DW signals recorded for ordinary and extraordinary polarization stem from an increased refractive index of at least Delta n > 2.10(-3) that originates from a tiny region of < 30 nm in width. PS-OCT hence provides an extremely valuable tool to decipher and quantify subtle changes of refractive index profiles for both inorganic and biomedical nanomaterial systems. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Details

Original languageEnglish
Pages (from-to)33615-33631
Number of pages17
JournalOptics express
Volume29
Issue number21
Publication statusPublished - 11 Oct 2021
Peer-reviewedYes

External IDs

Scopus 85116315290
ORCID /0000-0001-5283-0290/work/141545112
ORCID /0000-0002-8160-3000/work/142248328
ORCID /0000-0003-0554-2178/work/142249801
ORCID /0000-0002-2484-4158/work/142257520

Keywords

Keywords

  • LITHIUM-NIOBATE CRYSTALS, ELECTROOPTIC COEFFICIENTS, REFLECTIVITY, REFLECTANCE, DISPERSION, PROFILE