Continuous wave THz receivers with rhodium-doped InGaAs enabling 132 dB dynamic range
Milan Deumer, Steffen Breuer, Shaffi Berrios, Shahram Keyvaninia, Garrit Schwanke, Lauri Schwenson, Sebastian Lauck, Lars Liebermeister, Simon Nellen, Martin Schell, Robert B. Kohlhaas
Abstract
For the first time, we present photoconductive, continuous wave (cw) terahertz (THz) detectors for 1550 nm excitation based on rhodium- (Rh) doped indium gallium arsenide (InGaAs) grown by molecular beam epitaxy. Compared to iron- (Fe) doped material, the Rh-doped InGaAs shows higher carrier mobilities with similar carrier lifetimes. Therefore, these photoconductive antennas outperform InGaAs:Fe-based detectors by a factor of 10 in terms of responsivity and noise-equivalent-power (NEP) while maintaining the same bandwidth. In a homodyne spectrometer configuration, we achieve a record peak dynamic range (DNR) of 132 dB, which constitutes an improvement of 20 dB.