Electrooptic Ceramics Research Articles

La-doped PMN–PT transparent ceramics with ultra-high electro-optic effect and its application in optical devices

Transparent electro-optic (EO) ceramics of La-doped 0.75Pb(Mg_1/3Nb_2/3)O₃–0.25PbTiO₃ (0.75PMN–0.25PT) were prepared successfully. High transparency of 69% in the near-infrared (IR) wavelength (1550 nm) was achieved at 2 mol% La doping, meanwhile it shows an extremely high quadratic EO coefficient of 45.4×10⁻¹⁶ m²·V⁻², which is indispensable for applications in EO devices. The distribution of a polar nanodomain structure of the samples experiences disorder–order–disorder evolution in a La doping range. It is found that a parallelly-stacked polar nanodomain structure with an easier and faster polarization switching in the 2 mol% La-doped sample suggests that an ordering distribution of polar nanoregions would be critical to inducing large EO effect, transparency, and piezoelectric response. A triple-cavity tunable optical filter (TOF) with a single transmission peak and a tuning voltage below 30 V in a tuning range of 190–197 THz was designed based on our ceramics. The work is believed to bridge the relationship among doping-engineering, EO properties, and polarization behavior, which would guide the further optimization of transparent EO ceramics.

Continuous control of polarization state and tunable dual-channel optical communication based on highly transparent PMN-PT electro-optic ceramics

Transparent ferroelectric materials have excellent electro-optic properties, suitable to be used to develop high-performance optical communication devices. La-doped 88Pb(Mg1/3Nb2/3)O3–12PbTiO3 (88PMN-12PT) transparent ceramics with excellent comprehensive performances, including high transparency of 70.5% at near-infrared wavelength (close to its theoretical value), large quadratic electro-optic coefficient of 23.6 × 10−16 m2 V−2, low half-wave voltage (Vπ) of 146 V, and good extinction ratio of 34 dB, are successfully prepared in this paper. Based on the electro-optic effect of PMN-PT transparent ceramics, laser polarization state is transformed continuously from linear polarization to elliptical polarization, later to circularly polarization by applying electric field. Furthermore, dual-channel optical communication with a tunable laser intensity ratio is first reported here. Results indicate that PMN-PT transparent ceramic is a promising candidate for electro-optic material in polarization controller, optical switch, and information monitor in optical communication.

(Ba,Ca)(Ti,Zr)O3–CeO2 translucent and opaque ceramics — Optical and electromechanical characteristics

This work demonstrates promising approaches to synthesize multifunctional-translucent BCZT-CeO2 ceramic for electro-mechanical/optical conversion. Nearly fully dense BCZT-CeO2 electroceramics were fabricated by spark plasma sintering (SPS) showing high dielectric permittivity of 5875 and low dielectric loss of 2.1%. Altogether, an extraordinary optical transmittance was attained as ∼ 40% at 750 nm wavelength and ∼ 46% in the infrared region. The fine grains restricted piezoelectric constant, d33, to a moderate value of ∼ 145 pC/N but with an enhanced Curie temperature, TC ∼ 135 °C. Post rapid pressure-less sintering on SPSed samples led to a fast grain growth within an extra hour of sintering and a major improvement of piezoelectric properties (d33 = 532 pC/N and kp = 43%) was achieved. A substantial amount of energy can be saved by both approaches owing to rapid heating/cooling rates and short dwell-times, at least when compared to conventional sintering. This success highlights ingenious avenues for further studies on BCZT-CeO2 electro-optical ceramics.

Effects of Ba2+doping on microstructure and properties of PLMNT electro-optic ceramics fabricated by hot-pressed sintering process

A series of highly transparent electro-optic (EO) ceramics Pb0.975-xBaxLa0.025(Mg1/4Nb1/2Ti1/4)0.99375O3 with the Ba2+ content of 0, 0.005, 0.01, 0.02, 0.04 were fabricated through the vacuum/oxygen hot-press sintering process. The effects of the barium substitution on the material phase transition, transmittance, dielectric, ferroelectric and electro-optic properties have been investigated and analyzed. With the Ba2+ content increasing, the shape of the ferroelectric hysteresis loop changed from rectangular to slim, the values of remnant polarization (Pr) and coercive electric field (Ec) decreased obviously. The maximum reduction of Pr can reach up to ∼89.8%. All the samples present the high transparency of ∼68% in the near infrared wavelength. The quadratic EO coefficients declines slightly while the Ba2+ content increasing. When the x is 0.01, the sample shows a relatively larger quadratic EO coefficient of ∼30.42 × 10−16 (m/V)2 and a lower Pr value of ∼2.08 μC/cm2, which promise the material a hopeful application in EO modulator.

Effects of Ba2+Doping on Microstructure and Properties of Plmnt Electro-Optic Ceramics Fabricated by Hot-Pressed Sintering Process

Effects of Ba2+Doping on Microstructure and Properties of Plmnt Electro-Optic Ceramics Fabricated by Hot-Pressed Sintering Process

Enhancement in Dynamic Range of Amplitude-Modulated Continuous-Wave Laser Scanner Having a Coaxial Configuration

A laser scanner is a powerful tool for 3-D geometry measurement. The amplitude-modulated continuous-wave (CW) laser scanner, which benefits from high accuracy measurement operating in the intermediate range, is suitable for high-precision 3-D industrial inspection. However, due to the limited dynamic range, laser scanners suffer from data loss and deterioration. This poses challenges for 3-D modeling, conversion of 3-D point cloud data to 3-D solid data, and so on. We chose the operation wavelength in the 1530-nm region. The dynamic range of an amplitude-modulated CW laser scanner was enhanced by the implementation of a combination of a low-noise and high-gain optical preamplifier and p-i-n photodiodes, a pellicle beamsplitter, and automatic gain control using a polarization-independent high-speed variable optical attenuator based on electrooptic ceramics in the receiver. In these manners, receiver sensitivity of -72 dBm was achieved and receiver dynamic range of around 37 dB was realized. We expect that our results contribute to high-definition industrial inspection for Industry 4.0.

The electrical and optical properties of Nb-doping PLZT (9/65/35) transparent ceramics

In the past few decades, transparent electro-optical ceramics PLZT (9/65/35) (Pb0.91La0.09(Zr0.65Ti0.35)0.9775O3) with special properties, particularly high transmittance in visible light, have gained much attention. However, restricted by the large ferroelectric hysteresis, the prospect is not optimistic. In this article, Pb0.91La0.09(Zr0.65Ti0.35)0.9775-5x/4NbxO3 (abbreviated as PLZTN) transparent ceramics with varying Nb content (x = 0.000, 0.005, 0.010, 0.015) were fabricated by hot press sintering process under oxygen atmosphere. Electrical and optical properties were systematically studied. The temperature dependence of the dielectric constant showed a diffuse phase transition indicated typical relaxor behaviour. Moreover, the temperature at maximum dielectric constant (Tm) are near about 63 °C, almost unchanged. Comparing with undoped samples, the PLZTN with x = 0.010 Nb doping shows a dramatic reduction of 162.5% in ferroelectric hysteresis, with only a slight decrease in the maximum polarization from 30.04 µC/cm2 to 28.53 µC/cm2. The quadratic electro optic coefficient experienced 54.8% reduction but still satisfy the application requirements. In terms of transmittance, the PLZTN samples kept a high value of transmittance (about 64%) along with increasing Nb content. Hence, the conclusion can be drawn that Nb doping in PLZT (9/65/35) is a novel strategy to reduce the ferroelectric hysteresis.

The effect of Sn4+ doping on the electrostrictive property of PLZT (9/65/35) transparent electro-optical ceramics

SnO2-doped PLZT (9/65/35) transparent ceramics have been prepared by the hot press sintering method. The microstructure, dielectric, ferroelectric, and electrostrictive properties of the materials were examined and analyzed. All the samples present typical relaxor ferroelectric characteristics. Owing to the lowering of the long-range order by Sn4+ doping, the Tm peaks decrease gradually with the increasing SnO2 content. Compared with the high field-induced strains, the antiferroelectric-ferroelectric phase transformation in all the PLZST samples can be induced under the electric field. The electrostrictive property of the PLZT (9/65/35) ceramics was obviously improved by the Sn4+ ion doping. In addition, the polarization-related electrostrictive coefficient Q33 increased gradually from 0.024 m4/C2 to 0.027 m4/C2 as the SnO2 content increased from 0.0 wt % to 0.6 wt %.

Effects of barium substitution on the optical and electrical properties of PLZT transparent electro-optical ceramics

Abstract Transparent electro-optic (EO) ceramics Pb0.91-xLa0.09Bax(Zr0.65Ti0.35)0.9775O3 (PLBZT x/9/65/35) with the amount of x = 0, 0.01, 0.02, 0.04 barium substitution for Pb at A-site were fabricated by hot pressing sintering process. The effects of barium substitution on the micro structure, ferroelectric, dielectric, optical and electro-optic birefringence properties were systematically studied. XRD result shows a typical ABO3 perovskite structure and no second phase observed within the detection limit, which clarifies the entry of Ba2+ ions into PLZT that caused the expansion of the crystal lattice. Due to the mixing ion effect of Pb2+, Ba2+ and La3+ at A-site, both coercive field (Ec) and remnant polarization (Pr) show reducing tendency with increasing doping. And the temperature of the dielectric maximum (Tm) was decreased almost linearly with increasing barium modifying amount. Especially, the reduction of the ferroelectric hysteresis was observed, which may reveal the Ba doping a new method to solve the problems faced now in device designing. In summary, the easily tuned Tm and slim hysteresis loop may prove PLBZT a promising candidate for optical modulator, light switch, energy storage and other relevant applications.

Effects of Bi3+ Doping on the Optical and Electric-Induced Light Scattering Performance of PLZT (8.0/69/31) Transparent Ceramics.

Lanthanum modified lead zirconate titanate (abbreviated as PLZT) Electro-Optical ceramics with various Bi concentration were prepared by a hot-press process. The PLZT ceramic samples all present a single perovskite structure with no second phase detected. Bi3+ ion was considered to mainly enter the A-site of perovskite ABO3 structure of PLZT ceramics by the X-Ray Diffractionanalysis. The maximum permittivity (εm) of the PLZT samples decreased obviously as Bi concentration increased, while their remnant polarization (Pr) decreased slightly. In particular, the PLZT sample with 0.14 wt% Bi doping presented a higher optical transmittance 61.8% (λ = 633 nm), and its electric-induced light scattering performance was found to be improved obviously, the maximum light deduction value of ~47.6% was obtained.

Effects of Lanthanum Substitution on Dielectric, Ferroelectric and Electro-Optic Properties of Slim-Loop PLZT Ceramics

Highly transparent lead lanthanum zirconate titanate (Pb1−xLax)(Zr0.65Ti0.35)1-x/4O3(x=0.096-0.1) electro-optic ceramics were prepared by the hot pressing method. The ceramics exhibited transparency as high as 67% at 632.8nm (close to the theoretical value). The effects of lanthanum substitution on the phase structure, microstructure, dielectric, ferroelectric, optical and electro-optic properties of PLZT were examined systematically. The XRD results indicated that all the compositions were single perovskite phases, and La substitution decreased the lattice constant and unit-cell volume. The dielectric results showed that the Tmaxand εmaxdecreased with La content increasing. The hysteresis loops showed that the La content reduced saturate polarization (Ps), remnant polarization (Pr) and coercive field (Ec). Moreover, the half-wave voltage and EO coefficient R was enhanced and reduced respectively with increasing La.

Multifuncional translucent ferroelectric Ba1−xCaxTiO3 ceramics produced by laser sintering

Multifunctional transparent ferroelectric ceramics can be used in a wide range of applications, such as optical modulation and image memory devices, optical shutters, switchers, etc. Frequently, electro-optical ceramics are lead-based and have the disadvantages of being harmful to the environment. For this reason, continuous effort has been done in the research for lead-free optical transparent ferroelectric ceramics. In this work, we have successfully sintered bulk lead-free translucent and nanostructured Ba1−xCaxTiO3 (X=0–0.30) ceramics by the laser sintering technique. In this technique, a CO2 laser is used as the main heating source for sintering. The laser-sintered ceramics presented high relative density, suitable ferro- and dielectric properties, transmittance up to 42% at 950nm for Ba0.70Ca0.30TiO3 sample and average grain size changing from 420nm to 600nm when the Ca concentration increases.

Effects of Sintering Atmosphere on the PLMNT Transparent Ceramics Prepared by Hot-Press Sintering Method

La modified Pb(Mg1/3Nb2/3)O3-PbTiO3 (PLMNT) transparent electro-optic (EO) ceramics with pure perovskite phase were fabricated by the uniaxial hot-press sintering method. An improved hot-press sintering technique with varied atmosphere was proposed to eliminate the pore defects. It consists of four stages: 1) sintering at a relatively low temperature (800°C) in the vacuum atmosphere first, and then in the pure O2 atmosphere; 2) sintering in a pure O2 atmosphere at high temperature by uniaxial hot-press method; 3) replacing the O2 atmosphere with CO2 gas to eliminate the residual closed pores; 4) finally exchanging CO2 atmosphere with pure O2 gas to eliminate the oxygen vacancies. The research results certified that the thermal treatment in the vacuum atmosphere and CO2 atmosphere could eliminate the residual closed pores and improve the transmittance of the PLMNT transparent ceramics effectively. By the improved hot-press sintering technique, the optical transmittance of the polished PLMNT transparent ceramics with a thickness of 0.35mm increases from 61% to 64% at 632.8nm. The reasonable explanation was given about the mechanism of the improvements of this sintering technique.

Optical amplification in disordered electrooptic Tm3+ and Ho3+ codoped lanthanum-modified lead zirconate titanate ceramics and study of spectroscopy and communication between cations

Rare earth doped electro-optic (EO) ceramics of lanthanum-modified lead zirconate titanate (PLZT) are promising in building multifunctional optical devices, by taking advantage of both EO effect and optical activity. In this work, the combination of the measured spectra of absorption and photoluminescence, the fluorescent decay, the calculated Judd-Ofelt parameters, and measured single pass gain in Tm3+, Ho3+ codoped PLZT ceramics have marked them out as promising gain media in building electrically controllable lasers/optical amplifiers and other multifunctional devices. Optical energy storage was also observed in the optical amplification dynamics.

Influences of Excess PbO on Optical Properties and Microstructures of La Modified 0.75Pb (Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-0.25PbTiO<sub>3</sub> Electro-Optic Transparent Ceramics

La-modified 0.75Pb (Mg1/3Nb2/3)O3-0.25PbTiO3(PLMNT) electro-optic (EO) transparent ceramics were synthesized through a columbite precursor method. Excess PbO (10, 15 and 20 mol %) was added to study the effect on the transparency, electro-optic effect, and microstructures of PLMNT transparent ceramics. The phase structure of different samples can be identified as single perovskite structure with no second phase detected. The average grain size increased as the concentration of excess PbO increased from 10 mol% to 20 mol%. On the contrary, the transparency decreased with the increase of the concentration of excess PbO. When the concentration of excess PbO was 10 mol%, the transmittance was about 62% at 632.8nm. The EO coefficient was calculated through measuring the birefringence as a function of electric field. The EO coefficient increased with the increase of the concentration of excess PbO and the maximum EO coefficient reached 40.6×10-16(m/V)2 when the excess PbO was 20 mol%.

Fabrication of transparent electro-optic (K0.5Na0.5)1−xLixNb1−xBixO3 lead-free ceramics

Abstract Lead-free transparent electro-optic ceramics (K 0.5 Na 0.5 ) 1− x Li x Nb 1− x Bi x O 3 have been fabricated by hot-press sintering. Owing to the effective suppression of grain growth, the Li and Bi co-modified ceramics generally possess a dense and fine-grained structure. The co-modification also causes the ceramics to transform into a nearly cubic structure with minimal optical anisotropy. A diffuse phase transformation is also induced, causing the ceramics to become more relaxor-like and contain more polar nano-regions. These would reduce the light scattering by the grains, at the grain boundaries and at the domain walls, respectively, and thus making the ceramics become optically transparent. For the ceramic modified with 5 mol% Li + and Bi 5+ , the optical transmittance reaches a high value of 60% in the near-IR region. The ceramics also exhibit a strong linear EO response, giving a large effective linear EO coefficient in the range of 120–200 pm/V.

Iodine photodissociation laser with an intracavity space — time light modulator

A scheme of an iodine laser with two different intracavity space — time modulators based on electrooptic PLZT ceramics is experimentally studied. It is shown that lasing can occur in differentangular directions with the use of both modulators. The output laser energy is 10 mJ with a pulse duration of 200 μs and a beam divergence of 6.3 × 10-4 rad. The laser field of view (5.1 × 10-3 rad) consists of a discrete set of 8 × 8 directions.

Quadratic electro-optic properties of Pb(Mg1/3Nb2/3)O3-PbTiO3 transparent ceramics under both DC and AC bias

The basic quadratic electro-optic properties of Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) transparent ceramics have been studied under both DC and AC electric field bias. The contribution of piezoelectric resonance to electro-optic effect for this quadratic electro-optic ceramics material has been experimentally demonstrated and theoretically analyzed. It is found that, at the piezoelectric resonance frequencies, the piezoelectric induced electro-optic effect dominates and leads to a dramatically high sensitivity for weak electric signal detection. About 20 dB signal-to-noise ratio is attained when detecting AC electric field strength of 1 V/m with optimized DC bias. Besides, the effects of AC frequency and amplitude on halfwave voltage V(π) of PMN-PT are investigated.

Development of synthetic technology of multicomponent oxide powder materials and ferroelectric ceramics on their basis

The synthetic method of ultrafine multicomponent oxide powders of the composition of special-purity grade Pb(Sc0.5−xNb0.5Rx)O3 is developed. Optimal modes for obtaining a stable hydroxy polymer based on lead scandate-niobate in the form of a bound dispersed colloid system and the modes of its thermal treatment for obtaining stoichiometric powders with specific properties are established. The possibilities of optimizing the properties and fabrication technology of electrooptical ceramics via the introduction of modifying additives are considered.

Two-coordinate control of the radiation pattern of a chemical non-chain electric-discharge DF laser by using space—time light modulators

The results of studies of radiation parameters of a chemical non-chain DF laser (emitting in the range from 3.5 to 4.1 μm) with an intracavity control of the radiation pattern with the help of spatiotemporal modulators based on PLZT electrooptic ceramics are presented.