Direct writing of ferroelectric domains on the x- and y-faces of lithium niobate using a continuous wave ultraviolet laser

Abstract

Ferroelectric domain reversal has been achieved by scanning a tightly focused, strongly absorbed UV-laser beam across the x-and y-faces of lithium niobate crystals. The domains were investigated by piezoresponse force microscopy. The emergence and width of any domain was found to depend on the scanning direction of the irradiating laser beam with respect to the polar z-axis. Full width and half width domains, or no domain formation at all could be achieved for scanning along specific directions. We interpret the results by a direct correlation between the local temperature gradient and the resulting polarization direction.PACS numbers: 77.65.-j, 68.37. Ps, 77.80.Dj Lithium niobate (LiNbO 3 ) has recently become the material of first choice for nonlinear optical applications in the visible and near-infrared wavelength range. 1In many cases patterning of ferroelectric domains at a length scale of sub-to-few microns is required. For instance frequency conversion employing quasi-phase matching relies on a periodically poled domain pattern. 2Domain patterning is in general performed by electric field poling (EFP) with structured electrodes, which reverses the direction of polarization by locally applying an electric field along the polar z-axis of the crystal, exceeding the so-called coercive field (E c ). 3A different approach for domain patterning uses direct UV-laser beam writing.4 It was found that irradiating the −z-face of LiNbO 3 with a tightly focussed, strongly absorbed UV-laser beam creates ferroelectric domains along the laser-written track without any application of an external electric field. The very same procedure on the +z-face results in poling inhibition of the irradiated area.

Light‐Induced Reversible Control of Ferroelectric Polarization in BiFeO3

“…Light interacts with ferroelectrics in primarily two ways, that is, thermally or electronically. Absorption of high intensity laser illumination in ferroelectric materials, such as LiNbO 3 single crystals, raises the temperature locally close to the Curie temperature resulting in a giant temperature gradient and related thermal effect, for example, thermoelectric and pyroelectric effect, which is able to switch local ferroelectric polarization . However, this type of light‐induced polarization switching is irreversible and usually destructive …”

Ultraviolet direct domain writing on 128&#x00B0; YX-cut LiNbO<inf>3</inf>: For SAW applications

“…Recently, UV direct domain writing has been reported [7,8]. This domain engineering technique uses a focused UV laser beam for locally inverting the polarization of the LiNb03 crystal.…”

Sub-micron domain engineering in lithium niobate by laser light irradiation of patterned chromium

“…Recently, strongly absorbed UV laser light was employed to directly write domains in LiNbO 3 by scanning a focused UV laser beam (O = 244 nm) across the surface [4][5][6][7]. The domain inversion process is most likely due to a strong temperature gradient, which induces an electric field caused by the thermoelectric effect.…”