We report on a heterodyne receiver designed to observe the astrophysically important neutral atomic oxygen [OI] line at 4.7448 THz. The local oscillator is a third-order distributed feedback Quantum Cascade Laser operating in continuous wave mode at 4.741 THz. A quasi-optical, superconducting NbN hot electron bolometer is used as the mixer. We recorded a double sideband receiver noise temperature (T^DSB_rec) of 815 K, which is ~7 times the quantum noise limit (h{\nu}/2k_B) and an Allan variance time of 15 s at an effective noise fluctuation bandwidth of 18 MHz. Heterodyne performance was confirmed by measuring a methanol line spectrum.
@article{arxiv.1208.5776,
title = {Hot electron bolometer heterodyne receiver with a 4.7-THz quantum cascade laser as a local oscillator},
author = {Jenna L. Kloosterman and Darren J. Hayton and Yuan Ren and Tsung-Yu Kao and Neils Hovenier and Jian-Rong Gao and Teun M. Klapwijk and Qing Hu and Christopher K. Walker and John L. Reno},
journal= {arXiv preprint arXiv:1208.5776},
year = {2015}
}
Comments
12 pages, 5 figures; accepted for publication in the Applied Physics Letters