The role of defects in light induced domain inversion in lithium niobate

Abstract

PACS 42.65.Yj, 77.84.Dy, 78.55.Hx Using the tightly focussed laser beam within a confocal luminescence microscope we were able to induce electric space charge fields through photoionization of trace defects in lithium niobate. These fields are sufficient to selectively induce domain inversion when a additional external field is applied that is below the regular coercive field. Once a domain is nucleated it grows laterally in a direction that can be dictated by the laser. We studied the presence and the range of the space charge fields utilizing the electro-optical effect and the Stark shifts observed in emission spectra of Er 3+ ions.

Light Induced Ferroelectric Domain Nucleation in LiNbO₃ Crystal

“…To overcome the limitations associated with electric field poling, several alternative methods are under investigation. The research of the influence of UV light in ferroelectric domain inversion and the optical periodic poling has been reported for lithium tantalite [1,2], lithium niobate [3,4]. These experiments show that the UV light could lead to a reduction of coercive field of ferroelectric material such as lithium niobate.…”

The role of Jahn–Teller ions in the creation of domain structures in lithium niobate

“…However, stoichio metric crystals have yet to be grown industrially and are fabricated only in individual laboratories; we therefore normally dope the charge using such ions as Mg, Zn, and Er with the highest concentrations of 1-3 at % in order to reduce E s . In this respect, dop ing lithium niobate crystals with Jahn-Teller ions (Cr 2+ , Mn 3+ , Fe 2+ ) [1][2][3] with concentrations on the order of 10 -5 to 10 -3 at % is of the greatest interest. The considerable reduction in the required concentra tion of dopants is due to the presence of large quadru pole moments of Jahn-Teller ions directed opposite field E s .…”

Laser-induced preferential domain nucleation in hafnium-doped congruent LiNbO 3 crystal

“…The focused visible light has been used to directly write surface domains in undoped LiNbO 3 . 10,11 The influences of ultraviolet illumination on the poling characteristics of the undoped and Mg-doped LiNbO 3 were investigated. 12,13 The laser-induced reductions of nucleation fields in Mg-doped LiNbO 3 by the focused visible light have been reported.…”