Investigation of reflection-type cone condenser used for THz detectors

A low cost and easy to fabricate THz triangle cone condenser with a high condensing efficiency in comparison to Winston cone has been made. A simulation and experimental results on condensing efficiency of both triangle cone and Winston cone show good consistency at the wavelength of 632.8 nm. In the case of Triangle cone condenser at the terahertz spectral region, simulation result showed that the condensing efficiency becomes approximately 100% at normal incident. In contrast to this, the condensing efficiency of Winston cone decreases at normal incident owing to the loss due to reflection. In general, the triangle cone has a broader field of view (FOV) than Winston cone, it is improved by attaching a baffle to the condenser.