Incoherent terahertz (THz) sources can be compact, stable, reliable and cheaper alternative to coherent emitters for compact THz systems. Low power of incoherent THz emitters can be compensated by benefit from extremely high sensitivity of THz micro-detectors. Incoherent THz torch device based on Ga(As,Bi)/AlGaAs parabolic quantum well (PQW) is modeled, fabricated and experimentally investigated paying special attention to the THz spectral range and optical properties. The structures for optical characterization were grown using MBE technique on GaAs substrates. The experimental study was carried out to measure the absorption by intersubband transition of electrons in PQW using vacuum Fourier transform spectroscopy, conventional farinfrared Fourier transform spectroscopy and THz time-domain spectroscopy. Transmittance spectra dependence on temperature and photo-excitation of undoped structures for THz torch device is studied exploring impact of the PQW on THz spectra.

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Mindaugas Karaliunas, Justas Pagalys, Vytautas Jakštas, Ričardas Norkus, Andrzej Urbanowicz, Jan Devenson, Renata Butkute, Andres Udal, and Gintaras Valušis, "Spectral properties of incoherent terahertz torch based on parabolic Ga(As,Bi)/AlGaAs quantum wells," Proc. SPIE 11124, Terahertz Emitters, Receivers, and Applications X, 1112409 (Presented at SPIE Optical Engineering + Applications: August 11, 2019; Published: 6 September 2019); https://doi.org/10.1117/12.2528428.