Optical Induction and Erasure of Ferroelectric Domains in Tetragonal PMN‐38PT Crystals

Abstract

Furthermore, they show extremely high electro-optic (EO) and acousto-optic (AO) coefficients. [2] Recent studies of quadratic nonlinearity of Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMN-PT) crystals in powder form indicated their potential for nonlinear optics. [3] Because of these excellent properties, the relaxor-based ferroelectric crystals could be of great interest as piezoelectric phononic crystals (PPCs) or acoustic superlattices (ASLs) to confine and manipulate phonons for a wide range of applications, including acoustic filters, noise isolation, and heat managements. [4] Unlike the pure elastic phononic crystal, which usually consists of materials with different elastic moduli and/or mass densities, [5] the domain inversion phononic crystal (DIPC) is a monolithic entity within the single ferroelectric, making it more attractive in applications like surface acoustic wave (SAW) devices. [4a,b,6] Similarly, ferroelectrics with spatially modulated second-order optical nonlinear susceptibility χ (2) , also known as nonlinear photonic crystals (NPCs) or optical super lattices (OSLs), can be used to generate, shape, and manipulate optical waves at new frequencies [7] by utilizing the so called quasiphase matching (QPM). [8] However, the PT-relaxor ferroelectrics exhibit excellent piezoelectric and quadratic nonlinear optical properties, making them prominent candidates for realization of phononic and nonlinear photonic crystals which rely on spatially patterned ferroelectric domains. However, formation of domain patterns, especially in three dimensions, has been challenging. This paper presents the first experimental demonstration of localized ferroelectric domains and their 2D and 3D patterns inside 0.62Pb(Mg 1/3 Nb 2/3 )O 3 -0.38PbTiO 3 (PMN-38PT) single-domain crystals engineered with focused near-infrared femtosecond laser pulses. Two types of domains are optically induced. Primary domains are formed in the focal volume of the beam, and secondary domains appearing at higher laser power, in the shape of hollow cylindrical structures, are formed around the beam. A physical mechanism of optical domain inversion involving thermo electric and space charge fields is proposed. This study contributes to a deeper understanding of domain formation and structuring in PMN-PT relaxor-based ferroelectrics, paving the way to integrate electromechanical, acoustic, and nonlinear optical effects in a single crystal.

A Brief Review on Nonlinear Photonic Crystals Induced by Direct Femtosecond Laser Writing

“…Therefore, domain inversion is relatively easier to attain in PMN-38PT crystal than in LiNbO 3 . Recently, primary and secondary domain inversions were simultaneously achieved in PMN-38PT crystal by Sheng et al [128]. The nonlinear absorption of a femtosecond laser not only leads to a thermoelectric field, inducing a primary domain inversion at the focal region, but also generates free carriers inside it, leading to a secondary domain inversion around it (Figure 12c), depending on the laser beam power.…”

Reversible Optical Control of Polarization in Epitaxial Ferroelectric Thin Films

“…Local laser-induced heating, for instance, can be employed to reduce the coercive field upon approaching the Curie temperature. Simultaneously, temperature gradients can give rise to pyroelectric and thermoelectric fields, [10] which have been successfully utilized to switch the polarization locally in single crystals of LiNbO 3 . [11,12] The propensity of many ferroelectrics to degrade or even decompose under strong temperature gradients, however, has prevented a more widespread use of laser-induced heating to manipulate the ferroelectric polarization.…”

Creation of a Periodic Domain Structure in MgOLN by Femtosecond Laser Irradiation

“…This method is now considered as an effective and flexible instrument for local polarization reversal and the creation of stable periodical domain patterns [15,16]. It is important to emphasize that this technique is the only one that allows realizing domain formation in the crystal bulk, thus creating the 3D domain patterns [17][18][19][20]; moreover, it allows erasing the already written domains locally [21]. The method can be applied to any ferroelectric that is transparent in the near-infrared spectral range.…”

“…A one-step method without laser spot motion during 0.5 s irradiation (wavelength 800 nm, pulse frequency 76 MHz) was applied to create periodical 3D domain structures in various ferroelectric crystals, such as Sr 0.61 Ba 0.39 Nb 2 O 6 [17], 0.62Pb(Mg 1/3 Nb 2/3 )O 3 -0.38PbTiO 3 [18,24], and Ba 0.77 Ca 0.23 TiO 3 [20]. The created domains were arranged into several structures with cubic symmetry used for SHG measurements [17].…”

“…The created domains were arranged into several structures with cubic symmetry used for SHG measurements [17]. The formation of two types of ferroelectric domains was demonstrated [18]. Domains of the first type had a narrow, elongated shape-the "primary" domain.…”