Optical properties of BiB3O6 in the terahertz range
Li, Yang, Jingguo Huang, Zhiming Huang, Nazar Nikolaev, Grigory Lanskii, Alexander Mamrashev, and Yury Andreev. “Optical properties of BiB3O6 in the terahertz range.” Results in Physics 16 (2020): 102815.
We present the spectra of the refractive index and the absorption coefficient of BiB3O6 (BIBO) crystal measured by the means of terahertz time-domain spectroscopy in the frequency range of 0.18–2.75 THz. We observe a large birefringence Δn = n<subZ − n<subX = 1.5 and the values of absorption coefficients of all three axes to be less than 5 cm−1 in the range below 1 THz. We report weak absorption lines in the vicinity of 2.28 and 2.6 THz for the Z-axis. Our results show that at room temperature BIBO has a lower absorption than other popular oxygen-containing nonlinear crystals: β–BBO, LBO, KTP, and LN. Thus, we assume the crystal to be an efficient THz radiation generator under intense laser pumping.
“The study was carried out at the temperature of ~17 °C in transmission configuration with commercial terahertz time-domain spectrometer TeraPulse 4000 (TeraView, UK). The samples under study were stuck to the 4.8 mm diaphragm placed in the focal plane between elliptical mirrors of the spectrometer. The THz beam waist in the focal plane is about 4 mm for the lowest frequencies. Two wire-grid polarizers were additionally installed in front of the generator and detector correspondingly to increase the polarization contrast of the system since BIBO exhibit large birefringence. “