Bound-state third-order optical nonlinearities of germanium nanocrystals embedded in a silica host matrix

Date

2008

Authors

Yıldırım, H.
Bulutay, C.

Editor(s)

Advisor

Supervisor

Co-Advisor

Co-Supervisor

Instructor

BUIR Usage Stats
0
views
18
downloads

Citation Stats

Series

Abstract

Embedded germanium nanocrystals (NCs) in a silica host matrix are theoretically analyzed to identify their third-order bound-state nonlinearities. A rigorous atomistic pseudopotential approach is used for determining the electronic structure and the nonlinear optical susceptibilities. This study characterizing the two-photon absorption, nonlinear refractive index, and optical switching parameters reveals the full wavelength dependence from static up to the ultraviolet spectrum, and the size dependence up to a diameter of 3.5 nm. Similar to Si NCs, the intensity-dependent refractive index increases with decreasing NC diameter. On the other hand, Ge NCs possess about an order of magnitude smaller nonlinear susceptibility compared to Si NCs of the same size. It is observed that the two-photon absorption threshold extends beyond the half band-gap value. This enables nonlinear refractive index tunability over a much wider wavelength range free from two-photon absorption.

Source Title

Physical Review B - Condensed Matter and Materials Physics

Publisher

The American Physical Society

Course

Other identifiers

Book Title

Keywords

Degree Discipline

Degree Level

Degree Name

Citation

Published Version (Please cite this version)

Language

English