Fig. 1. X-ray diffraction pattern of 0.3BaSrTiO₃-0.7NdAlO₃ ceramics

Fig. 2. Installation diagram of THz-TDS. A 532 nm laser is obliquely incident upon the surface of the sample at an angle of 45° with the polar axis

Fig. 3. Terahertz time domain waveform of 0.3BaSrTiO₃-0.7NdAlO₃ ceramics. (a) Time-domain reference and transmission waveforms;(b) time shift under different external optical pump fields at 18 ℃

Fig. 4. Transmission spectra of 0.3BaSrTiO₃-0.7NdAlO₃ ceramics under different external optical pump intensities at 18 ℃

Fig. 5. Frequency dependence of complex permittivity of 0.3BaSrTiO₃-0.7NdAlO₃ under different external optical pump intensities at 18 ℃. (a) Real part; (b) imaginary part

Fig. 6. Light power as a function of the dielectric constant of 0.3BaSrTiO₃-0.7NdAlO₃ ceramics at 0.45 THz and 0.55 THz

Fig. 7. Absorption coefficients changed with frequency and optical power in 0.3BaSrTiO₃-0.7NdAlO₃. (a) Frequency; (b) optical power

Fig. 8. Tunability of the loss tangent of 0.3BaSrTiO₃-0.7NdAlO₃ ceramics at 0.45 THz and 0.55 THz as a function of the power at 18 ℃

Fig. 9. Variations of refractive index dependent on the optical power at 0.45 THz and 0.55 THz for 0.3BaSrTiO₃-0.7NdAlO₃ ceramics