Optical properties of BiB3O6 in the terahertz range

Abstract

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 = nZ − nX = 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.

Keywords

• BiB3O6
• Nonlinear crystal
• Terahertz time-domain spectroscopy
• Refractive index
• Absorption coefficient