Contents I. Introduction
In the past ten years, terahertz (THz) time-domain spectroscopy (TDS) has transitioned from a purely scientific technique to a promising tool in industry and applied science [1]. This development has been driven by the rapid advancements of ultrafast fiber lasers at 1550 nm and by the progress in photoconductive antennas (PCAs) that absorb this radiation and are used as THz emitters and receivers. As a result, fiber-coupled TDS systems are now compact, reliable and ready-to-use in industrial environments [2], [3]. However, the maximum bandwidth of these systems has so far been limited to 6.5 THz, despite significant improvements in their dynamic range [4]. This limitation impairs the resolution in applications such as layer thickness determination and imaging. Therefore, accessing the full bandwidth of up to 10 THz is desirable. Here, we present photoconductive membrane (PCM) antennas on silicon, which overcome the limitations of state-of-the-art PCAs and in this way enable 10 THz bandwidth with a fiber-coupled TDS system.
