The optical transparency investigation of crystals based on the AgHal – TlHal solid solutions systems in the terahertz range

This article examines the transmission spectra of crystals based on the AgCl − AgBr, AgBr − TlI, AgBr − TlBr0.46I0.54 (KRS-5), AgBr − AgI systems in the visible, infrared, and terahertz ranges. We've determined the optical characteristics in the terahertz range for polycrystalline plates obtained by hot embossing based on silver and thallium halides' solid solutions. As a study result, silver and thallium (I) halides have demonstrated competitive transmission characteristics both in the visible and infrared spectra also in the THz frequency range. The transmission range for crystals of the AgCl − AgBr system was 0.45–30.0 μm (9.9–666.2 THz) and 250–6000 μm (0.05–1.19 THz) with optical transparency reaching 78%, for crystals of the AgBr − AgI, AgBr − TlI, AgBr − TlBr0.46I0.54 systems, 47.0–60.0 μm (4.9–6.3 THz) and 250–6000 μm (0.05–1.19 THz) with optical transparency reaching 76%. At the same time, in the long-wavelength infrared region from 800 to 6000 μm (0.05–0.37 THz) the absorption coefficient’ value hasn't exceeded 0.1 cm−1 for the AgCl − AgBr crystal system, also lied within 0.1–0.005 cm−1 for the AgBr − AgI, AgBr − TlI, AgBr − TlBr0.46I0.54 crystals systems. •Silver and thallium (I) halide in the region 800.0–6000.0 μm is transparent.•The absorption coefficient is 0.1–0.025 сm−1 and 0,1–0,005 сm−1.•Spectral oscillations in the low-frequency THz region are inharmonic.