Optical tuning of absorption coefficient and dielectric properties of amorphous Cu doped α-Fe2O3 in the THz range

In this paper, we reported amorphous (Cu x Fe1−x )2O3 (x = 0.1, 0.2, and 0.3) ceramics with absorption coefficient and dielectric properties tunable by an external optical field. The materials are prepared by a co-precipitation technique. X-ray diffraction analysis reveals that the samples are amorphous materials. The transmittance spectra in the terahertz range (0.2–1 THz) of (Cu x Fe1−x )2O3 (x = 0.1, 0.2, and 0.3) ceramics were investigated at room temperature. With the application of an external optical field (400 mW), the absorption coefficients, the dielectric constants and loss tangents of all the samples can be tuned in the terahertz range. The dielectric constant can be tuned up to 79% for the sample with x = 0.3 and the absorption coefficient can be tuned up to 87% for the sample with x = 0.2 at 0.3 THz with the external optical field. The optical tuning effect is induced by the suppressing of the electron hopping between Fe3+ to Fe2+ and the decrease of oxygen vacancies caused by the optical field.