# Progress in Transparent Nano-Ceramics and Their Potential Applications
## 5 Other Transparent Nano-Ceramics
### Electro-Optical Transparent Nano-Ceramics
The coercive electric field and the polarization curve are similar, indicating that there is some interaction between the ferroelectric phase and the magnetoelectric phase. In 2021, [PERSON] et al. [97] prepared PMN-PT materials using a two-step sintering method. The thickness of the small ceramic was 0.85 mm, and the diameter was 10 mm. The thickness of the large ceramic was 1 mm, and the diameter was also 10 mm. After testing, it was found that as the wavelength gradually increased to 900 nm, the transmittance gradually increased to 70%. When Sm was doped, the peak value of optical power would move back. However, the basic rule was that with the increase in electric field intensity, the optical power gradually increased to 100% and then continued to decrease. [PERSON] et al. [98] prepared PMN-platinum piezoelectric ceramics using the solid-state reaction method and analyzed the microstructure of the four fractured and sintered samples by scanning electron microscopy and found that their average particle sizes were 2.7, 3.2, 3.8, and 4.3 \(\upmu\)m, respectively (Figure 16). Table 3 summarizes the representative papers on the preparation of electro-optically transparent nano-ceramics, mainly including the powder, fabrication and remarks. Figure 16: SEM images of PMN-PT polycrystals; (**a**) 1275 \({}^{\circ}\)C, 30 min: average grain size (2.7 \(\upmu\)m); (**b**) 1275 \({}^{\circ}\)C, 60 min: average grain size (3.2 \(\upmu\)m); (**c**) 1300 \({}^{\circ}\)C, 90 min: average grain size (3.8 \(\upmu\)m); (**d**) 1300 \({}^{\circ}\)C, 120 min: average grain size (4.3 \(\upmu\)m) [98]. Reprinted with permission from Ref. [98]. Copyright 2019, copyright ScienceDirect. At this stage, electro-optic transparent ceramics are mainly used in electro-optic modulators, high-speed electro-optic switches, and ultrasonic transducers. Next, we will analyze these devices in detail. Firstly, using the electronically controlled refraction effect in the electro-optical material, the electro-optical transparent ceramic is prepared as an electro-optical modulator, in which the basic parameters such as the frequency and phase of the light beam can be determined by the characteristics of the electro-optical material. This can provide higher working accuracy, greater working reliability, and stronger anti-interference ability. The use of this modulator can minimize the degradation of the optical fiber system and increase the life of the equipment [107]. In addition, electro-optic transparent ceramics can also be used in high-speed electro-optic switches. The main working principle is to use the electronically controlled refractive index of electro-optic materials to adjust and use optical signals to control the switch. Moreover, the electro-optic material has good light transmittance, a high electro-optic coefficient, and a low cost, which have a great guiding effect on the development of electrical components in the future. However, the LiNbO\({}_{3}\) crystal is mainly used in the existing electro-optic switch. There are still some defects, and the process of selecting the crystal axis when transmitting light is more complicated [108]. Moreover, PLZT ceramic materials have small diameters, good dielectric and piezoelectric properties, and good electromechanical coupling coefficients, which can be used in medical imaging technology and ultrasonic transducers. After using the transparent optical fiber as the main component, the size of the material and the damage to the surrounding materials, such as laser cutting, can be reduced to a limited extent. Additionally, the use of this material can improve the resolution of the device and increase the working accuracy [109]. Furthermore, this study found that when PMN-PT and polyvinylidene fluoride (PVDF)