Machinable ceramic for high performance and compact THz optical components

The properties of Shapal Hi-M Soft, an aluminum nitride based ceramic, as a material for THz optical components are investigated and compared with other ceramic materials. Shapal is a low-cost and machinable ceramic with a high-refractive index and low losses at THz frequencies: n = 2.65, α = 0.4 cm−1. To demonstrate the shaping capabilities, a Fresnel lens is fabricated with a micro-milling system. Additionally, a prism as an example of a bulk component is demonstrated. Both a THz time domain spectrometer and a vector network analyzer (0.75–1.1 THz) are used for the optical characterization and the absorption coefficient is precisely obtained in the VNA frequency range.