Continuous wave THz receivers with rhodium-doped InGaAs enabling 132 dB dynamic range

• DOI: 10.1364/oe.532465
• Publication Date: 2024-07-26T10:00:09Z
• Authors: Milan Deumer; Steffen Breuer; Shaffi Berrios; Shahram Keyvaninia; Garrit Schwanke; Lauri Schwenson; Sebastian Lauck; Lars Liebermeister; Simon Nellen; Martin Schell; Robert B. Kohlhaas
• Keywords: 02 engineering and technology; 0210 nano-technology

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.