Liquid Crystals Beyond Displays: Chemistry, Physics, and Applications

Chapter 4

Ferroelectric Liquid Crystals for Nonlinear Optical Applications

Yongqiang Zhang

Micron Technology, Inc., Longmont, Colorado, USA

Jesús Etxebarria

Department of Condensed Matter Physics, University of the Basque Country, Bilbao, Spain

4.1 Introduction

4.1.1 Overview of Nonlinear Optical Materials (NLO) and Electro-Optic (EO) Materials

NLO materials have become increasingly indispensable to today's EO technology. Electro-optics involve these two important technologies (electronics and photonics), and the interdisciplinary field requires expertise from many fields such as mathematics, physics, chemistry, material science, electrical, and optical engineering. Electrons perform information functions in electronic devices, while photons are capable of performing the same functions in photonic devices at much faster speed but without production of too much heat. EO devices provide a means of converting information from the electronic domain to the photonic domain or vice versa. They have been widely used in telecommunication systems, and are particularly attractive in emerging optical computing applications.

Since the discovery of second harmonic generation (SHG) in inorganic materials in 1961 [1], a variety of inorganic crystalline materials including lithium niobate (LiNbO₃), potassium niobate (KNbO₃), potassium titanyl phosphate (KTiOPO₄), and potassium dihydrogen phosphate (KH₂PO₄), etc., have been successfully developed. Today's EO and NLO commercial markets are completely ...