Poling

About: Poling is a research topic. Over the lifetime, 2957 publications have been published within this topic receiving 51205 citations.

Large second-order nonlinearity in poled fused silica.

Abstract: A large second-order nonlinearity [ χ(2)~1 pm/V~0.2 χ22(2) for LiNbO3] is induced in the near-surface (~4 μm) region of commercial fused-silica optical flats by a temperature (250–325°C) and electric-field (E ~ 5 × 104 V/cm) poling process. Once formed, the nonlinearity, which is roughly 103–104 times larger than that found in fiber second-harmonic experiments, is extremely stable at room temperature and laboratory ambient. The nonlinearity can be cycled by repeated depoling (temperature only) and repoling (temperature and electric field) processes without history effects. Possible mechanisms, including nonlinear moieties and electric-field-induced second-order nonlinearities, are discussed.

Second harmonic generation in poled polymer films

Abstract: We report the observation of second harmonic generation in a new class of organic polymeric materials, namely, electric field poled polymer glasses. Both the observed second harmonic coefficient (d33=6.0±1.3×10−9 esu, at 1.58 μm wavelength) and the poling process are described by a thermodynamic model that we have developed. The ability to form thin films from these materials may qualify them for integrated optics applications.

Measurement of piezoelectric coefficients of ferroelectric thin films

Abstract: This article presents measurements of piezoelectric coefficients of lead zirconate titanate (PZT) thin films. The normal load method is used to measure the coefficients for PZT films with various compositions prepared by the sol‐gel technique or by organometallic chemical vapor deposition (OMCVD). The as‐deposited OMCVD films have a piezoelectric coefficient of 20–40×10−12 m/V, whereas the unpoled sol‐gel films are not piezoelectric. After poling the thin films having a composition near the morphotropic phase boundary; these values increase to 200×10−12 m/V for OMCVD films and 400×10−12 m/V for sol‐gel films. The difference may arise from an incomplete poling of the OMCVD films.

Second-harmonic generation and absorption studies of polymer-dye films oriented by corona-onset poling at elevated temperatures

Abstract: Second-harmonic generation and spectroscopic absorption measurements are used to study the nonlinear-optical thin-film properties of azo dye guest molecules oriented in a polymer host by corona-onset poling at elevated temperatures (COPET). Parallel-wire electrode and needle electrode configurations are studied. The orientational order of the nonlinear molecules, the internal electric field, and the stability of the second-harmonic properties are measured. The nonlinear properties stabilize after 10 days and remain relatively constant over a period of at least 8 months, and the films tolerate power densities of at least 60MW/cm2. Compared with other poling methods, COPET produces a more efficient long-range and long-term orientational order in the guest–host system studied, resulting in large, stable second-harmonic properties.

Processing and Electromechanical Properties of (Bi0.5Na0.5)(1−1.5x)LaxTiO3 Ceramics

Abstract: Bismuth sodium titanate (Bi0.5Na0.5TiO3, BNT) with 0–6 at.% lanthanum was prepared by the conventional mixed oxide method. Each composition was calcined at 800–900°C for 2–5 h to form a pure perovskite phase. Green pellets were sintered at 1050–1150°C for 1–4 h to obtain dense ceramics with at least 95% of theoretical density. X–ray diffraction (XRD) showed phase distortion as lanthanum was added to this system. Meanwhile, a small amount of La was found to affect the grain size and had an influence on the poling conditions and electrical properties. The BNT–based composition with 1 at.% La doping provided a dielectric constant (K) of 560, a piezoelectric charge constant (d33) of 92 pC/N, and a hydrostatic piezoelectric coefficient (dh) of 72 pC/N.