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Title: Anomalous laser deflection phenomenon based on the interaction of electro-optic and graded refractivity effects in Cu-doped KTa{sub 1−x}Nb{sub x}O{sub 3} crystal

Abstract

An abnormal laser deflection phenomenon in a copper-doped KTa{sub 1−x}Nb{sub x}O{sub 3} (Cu:KTN) crystal is demonstrated in this Letter. A near-50 mrad beam deflection angle was observed when a voltage of 1.2 kV was applied to a Cu:KTN block with size of 2.8 mm × 1.2 mm × 7.5 mm at room temperature. The special features of this deflection phenomenon are that the laser beam deflection direction is perpendicular to the electric field direction, and the beam deflection angle remains unchanged when the electric field direction is reversed. The operating principle of the phenomenon is investigated and the origin of the deflection phenomenon is attributed to an interaction between the graded refractivity effect and the quadratic electro-optic effect of the crystal.

Authors:
; ; ; ;  [1]; ;  [2]; ;  [3]
  1. New Materials Institute, Shandong Academy of Sciences, Jinan 250014 (China)
  2. Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China)
  3. State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China)
Publication Date:
OSTI Identifier:
22314484
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COPPER; CRYSTALS; DOPED MATERIALS; ELECTRIC FIELDS; LASERS; NIOBIUM COMPOUNDS; OXYGEN COMPOUNDS; POTASSIUM COMPOUNDS; REFRACTIVE INDEX; TANTALUM COMPOUNDS

Citation Formats

Wang, Xuping, E-mail: wangxp@sdas.org, Liu, Bing, Yang, Yuguo, Zhang, Yuanyuan, Lv, Xianshun, Hong, Guanglie, Shu, Rong, Yu, Haohai, and Wang, Jiyang. Anomalous laser deflection phenomenon based on the interaction of electro-optic and graded refractivity effects in Cu-doped KTa{sub 1−x}Nb{sub x}O{sub 3} crystal. United States: N. p., 2014. Web. doi:10.1063/1.4892663.
Wang, Xuping, E-mail: wangxp@sdas.org, Liu, Bing, Yang, Yuguo, Zhang, Yuanyuan, Lv, Xianshun, Hong, Guanglie, Shu, Rong, Yu, Haohai, & Wang, Jiyang. Anomalous laser deflection phenomenon based on the interaction of electro-optic and graded refractivity effects in Cu-doped KTa{sub 1−x}Nb{sub x}O{sub 3} crystal. United States. doi:10.1063/1.4892663.
Wang, Xuping, E-mail: wangxp@sdas.org, Liu, Bing, Yang, Yuguo, Zhang, Yuanyuan, Lv, Xianshun, Hong, Guanglie, Shu, Rong, Yu, Haohai, and Wang, Jiyang. Mon . "Anomalous laser deflection phenomenon based on the interaction of electro-optic and graded refractivity effects in Cu-doped KTa{sub 1−x}Nb{sub x}O{sub 3} crystal". United States. doi:10.1063/1.4892663.
@article{osti_22314484,
title = {Anomalous laser deflection phenomenon based on the interaction of electro-optic and graded refractivity effects in Cu-doped KTa{sub 1−x}Nb{sub x}O{sub 3} crystal},
author = {Wang, Xuping, E-mail: wangxp@sdas.org and Liu, Bing and Yang, Yuguo and Zhang, Yuanyuan and Lv, Xianshun and Hong, Guanglie and Shu, Rong and Yu, Haohai and Wang, Jiyang},
abstractNote = {An abnormal laser deflection phenomenon in a copper-doped KTa{sub 1−x}Nb{sub x}O{sub 3} (Cu:KTN) crystal is demonstrated in this Letter. A near-50 mrad beam deflection angle was observed when a voltage of 1.2 kV was applied to a Cu:KTN block with size of 2.8 mm × 1.2 mm × 7.5 mm at room temperature. The special features of this deflection phenomenon are that the laser beam deflection direction is perpendicular to the electric field direction, and the beam deflection angle remains unchanged when the electric field direction is reversed. The operating principle of the phenomenon is investigated and the origin of the deflection phenomenon is attributed to an interaction between the graded refractivity effect and the quadratic electro-optic effect of the crystal.},
doi = {10.1063/1.4892663},
journal = {Applied Physics Letters},
number = 5,
volume = 105,
place = {United States},
year = {Mon Aug 04 00:00:00 EDT 2014},
month = {Mon Aug 04 00:00:00 EDT 2014}
}
  • In the present paper, dielectric, polarization, and Raman results have been combined to identify the existence of a ferroelectric phase transition in the substitutionally disordered dipolar system, KTa{sub 1{minus}{ital x}}Nb{sub {ital x}}O{sub 3}, for low Nb concentrations ({ital x}=1.2%). A detailed study of the first-order TO{sub 2} and TO{sub 3} Raman lines reveals (1) the existence of polar microregions well above {ital T}{sub {ital c}} and (2) the structural transition at {ital T}{sub {ital c}} with the appearance of ferroelectric macroregions. Similar results are obtained in K{sub 1{minus}{ital y}}Li{sub {ital y}}TaO{sub 3} with a quantitative difference due to the slowmore » reorientation of Li. These results can be explained by a random-field model which predicts the coexistence of both dipolar glass and ferroelectric behavior.« less
  • High-resolution x-ray diffraction measurements have been performed between 10 and 300 K on several single crystals of KTa{sub 1{minus}{ital x}}Nb{sub {ital x}}O{sub 3} with {ital x}{le}0.157. Contary to the published phase diagram, no deviation from cubic symmetry is seen for {ital x}{le}0.060. Instead, a low-temperatue minimum to the cubic unit cell volume is observed at a temperature {ital T}{sub min} which increases monotonically for 0.012{le}{ital x}{le}0.060. Data for {ital x}=0.157, however, are consistent with the previously established sequence of structural transitions from cubic to tetragonal to orthorhombic to rhombohedral symmetries. We associate {ital T}{sub min} with the onset of amore » dipolar glass transition. In addition, a radial broadening of the linewidths is observed at {ital T}{sub min}, indicating the presence of strain in the lattice. Powdering small pieces from these single crystals suppresses the unit cell minimum and stabilizes the cubic phase down to 10 K, even for {ital x}=0.157.« less
  • Fast nonlinear optical signals on picosecond and nanosecond time scales have been studied in the mixed crystal system KTa{sub 1{minus}{ital x}}Nb{sub {ital x}}O{sub 3} using transient degenerate four-wave mixing. The two distinct signal components, denoted as an instantaneous response and slow response in previous studies, show the dependence of the polarization configuration of the optical pulses. The results were consistent with a lattice-relaxation model based on the laser-induced dynamic displacement of the Nb ion. In this model the signal variations result from the competition between the dynamic displacement and the intrinsic distortion associated with the spontaneous polarization along the opticmore » axis.« less
  • A study of the properties of laser-induced transient gratings produced in KTa{sub 1{minus}{ital x}}Nb{sub {ital x}}O{sub 3} crystals by picosecond-pulse, two-photon excitation was carried out with use of degenerate-four-wave-mixing techniques. The grating properties were found to depend on the Nb concentration. The diffraction efficiency of the gratings exhibited a maximum at an intermediate Nb concentration while the signal decay rate increased uniformly with {ital x}. A lattice-relaxation model was developed to explain the experimental results that includes the intrinsic lattice distortion due to the niobium ions in the normally cubic perovskite crystal and the strong electron-phonon interaction causing a latticemore » distortion around photoionized ions. The predictions of the theoretical model agree with the experimental data. The results of grating decay-rate measurements show that the excited states produced by two-photon laser excitation act as localized quasiparticles (excitons or polarons) having a hopping rate that increases with Nb concentration {ital x}. Strong electron-phonon coupling produces phonon-assisted, incoherent hopping migration.« less
  • The understanding of the spin gap phenomenon in the normal state of the high temperature superconductors can provide the mechanism of the high temperature superconductivity. A specific function of thermal excitation for quasiparticles was introduced based on the experimental relationship between resistivity and temperature. This specific function describes the deviation in resistivity from the T-linear relationship w.r.t. the normal state of the high temperature superconductors. With this function, the spin gap is naturally introduced. The experimental results indicate that the spin gap behavior is closely related not only to the oxygen deficiency but also to the structural change in themore » a-b plane. Furthermore, the authors found that the crossover from anomalous metallic state to spin gap state takes place within a temperature range T{sub S} {lt} T {lt} T*, which depends on the oxygen content and the Ca-doping level. Pressure effects on the spin gap phenomenon in bulk samples of oxygen-deficient YBa{sub 2}Cu{sub 3}O{sub 6+{delta}} and Ca-doped Y{sub 1{minus}x}Ca{sub x}Ba{sub 2}Cu{sub 3}O{sub 6+{delta}} were also investigated. Under high hydrostatic pressure the spin gap behavior is also severely influenced by the contraction of the a-b plane due to the pressure.« less