Threshold conditions for bulk second-order nonlinearity and near-surface second-order nonlinearity in thermally poled Infrasil silica (original) (raw)
Related papers
Optical Review, 2001
Generation of bulk second-order nonlinearity in silica glass requires higher poling temperature or longer poling time than that of near-surface second-order nonlinearity. The threshold conditions for initiating the bulk second-order nonlinearity are studied on Infrasil fused silica glass. The threshold poling time is strongly dependent on the poling temperature. The near-surface second-order nonlinearity is also studied, especially the dependence of thickness of the nonlinear layer on the poling temperature, poling voltage and poling time. Secondary-ion mass-spectroscopy measurement showed depletion of Na+ ions at the anodic surface.
Dynamics of the second-order nonlinearity in thermally poled silica glass
Applied Physics Letters, 2001
We study the temporal evolution of both the second-order nonlinear coefficient and of the nonlinear thickness in thermally poled silica-glass slides by using a high-resolution all-optical technique. A time delay in the nonlinearity formation is observed, followed by an increase to a maximum, and a final decrease. The thickness is shown to increase at a rate that differs significantly from that reported for the corresponding ionic charge fronts. Our measurements also show strong dependencies on sample thickness and these can be attributed to different electric fields in the depletion region.
Large second-order nonlinearity in poled fused silica
Optics Letters, 1991
A large second-order nonlinearity [x( 2 ) -1 pm/V -0.2 X222 for LiNbOd] is induced in the near-surface (-4 Am) region of commercial fused-silica optical flats by a temperature (250-325 0 C) and electric-field (E -5 x 10 4 V/cm) poling process. Once formed, the nonlinearity, which is roughly 10 3 -10 4 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.
IEEE Photonics Technology Letters, 2000
Thermally poled fused silica glass was characterized with second-harmonic optical and scanning electron microscopy. It was found that, along with the creation of a second-order nonlinearity (SON) layer under the anode surface, a layer of nanometersized crystalline particles exists near the anode surface. Its spatial distribution, as well as the average crystal size, was measured and compared with that of the induced SON.
Influence of different poling methods on the second-order nonlinearity in fused silica glasses
Optics Communications, 2000
Fused silica glass samples poled by different methods showed large differences in their second-order optical nonlinearities. Large second-harmonic signals were obtained only when a depletion layer was formed near the anode surface. By comparing the influences of plate poling and corona poling, the necessary conditions to form a depletion layer in fused silica glass are discussed.
Time evolution of second-order nonlinear profiles induced within thermally poled silica samples
Optics Letters, 2005
The second-order nonlinear profile induced within thermally poled Infrasil silica samples is characterized as a function of the duration of the poling process. For poling durations shorter than 5 min the spatial distribution of the ͑2͒ susceptibility exhibits a triangular shape. This observation, as well as the maximum value of the electric field recorded during poling ͑1.9ϫ 10 9 V/m͒, is in excellent agreement with charge migration models that involve a single charge carrier. It is shown that for higher poling durations the nonlinear profiles tend to flatten; in that case the charge injection mechanisms cannot be neglected. For another point of view, the experimental method introduced herein has allowed us to determine the mobility of the rapid charge carrier involved in the poling process: = 1.5ϫ 10 −15 m 2 V −1 s −1 at 250°C.
Journal of the Optical Society of America B, 2006
Soda-lime silicate (SLS) glasses were thermally poled at 230°C -280°C with dc voltages up to 2 kV applied to induce a second-order optical nonlinearity. Accompanying structural modifications to the thermally poled SLS glasses were investigated with scanning electron microscopy. On the cathode surface, sodium metasilicate crystals were formed through the reduction of migrating sodium ions at the cathode. At the anode, intense phase separation occurred within several micrometers beneath the anode surface during the thermal poling process. These structural modifications are attributed to the electric field enhancement effect. The second-order nonlinearity induced in such poled samples was found to still be present after a long period of high-temperature annealing, perhaps mainly due to a hindering effect from the phase separation and/or accumulated calcium ions to the recombination of space charges.
Physical Review A, 2002
The creation of a second-order nonlinear susceptibility (2) in thermally poled silica glasses is known to be related to positive charge migration. As opposed to currently used models, we herein propose a model that takes into account charge dissociation and charge recombination occurring during the poling process. This model, known as the Proctor and Sutton model, was used to determine the space-charge distribution within silica plates submitted to an electric field. In this paper, we perform theoretical calculations in order to adapt this model to the high values of the applied electric field during the poling process. Moreover, we prove that there is a voltage threshold below which no (2) can be induced. We also point out the existence of a nonzero electric field within the entire sample. To test the validity of this model, we poled 1 mm thick Infrasil™ silica slabs using voltages ranging from 0 to 4 kV. Maker fringe patterns have been recorded in order to estimate the magnitude of the induced nonlinear (2) coefficient. We report experimental evidence of a poling voltage threshold of 900 V in these samples.
2010
This paper describes progress in characterizing the distribution and localization of the second-order nonlinearity induced in thermally poled silicate glasses and optical waveguides, in particular, optical fibers. It starts by describing the basics of the poling technique, especially the most commonly used "thermal poling" technique. Then results of systematic investigation of the distribution of the second-order nonlinearity in poled glass and special fibers using second-harmonic microscopy are presented. Interesting issues such as the effectiveness of the poling technique for waveguides formed by ultrafast laser pulses are also discussed.