@article{213c44accaaf48d4b890802555c9e81e,
title = "8-beam local oscillator array at 4.7 THz generated by a phase grating and a quantum cascade laser",
abstract = "We present an 8-beam local oscillator (LO) for the astronomically significant [OI] line at 4.7 THz. The beams are generated using a quantum cascade laser (QCL) in combination with a Fourier phase grating. The grating is fully characterized using a third order distributed feedback (DFB) QCL with a single mode emission at 4.7 THz as the input. The measured diffraction efficiency of 74.3% is in an excellent agreement with the calculated result of 75.4% using a 3D simulation. We show that the power distribution among the diffracted beams is uniform enough for pumping an array receiver. To validate the grating bandwidth, we apply a far-infrared (FIR) gas laser emission at 5.3 THz as the input and find a very similar performance in terms of efficiency, power distribution, and spatial configuration of the diffracted beams. Both results represent the highest operating frequencies of THz phase gratings reported in the literature. By injecting one of the eight diffracted 4.7 THz beams into a superconducting hot electron bolometer (HEB) mixer, we find that the coupled power, taking the optical loss into account, is in consistency with the QCL power value.",
author = "B. Mirzaei and Silva, {J. R.G.} and D. Hayton and Christopher Groppi and Kao, {T. Y.} and Q. Hu and Reno, {J. L.} and Gao, {J. R.}",
note = "Funding Information: U.S. Department of Energy's National Nuclear Security Administration (DE-NA-0003525). One of the authors (B. M.) acknowledges the support and encouragement from Leo Kouwenhoven. We also acknowledge useful discussions with Chris Walker, Kobus Kuipers, Paul Urbach, and Akira Endo. The authors would like to thank Yuchen Luo for making his grating codes available for this work, Matt Underhill for fabricating the gratings and David Thoen for helping with the surface profile measurements. EU RadioNet and TU Delft Space Institute are acknowledged for their supports. The work at MIT was supported by NASA. The work at Sandia was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration. Funding Information: One of the authors (B. M.) acknowledges the support and encouragement from Leo Kouwenhoven. We also acknowledge useful discussions with Chris Walker, Kobus Kuipers, Paul Urbach, and Akira Endo. The authors would like to thank Yuchen Luo for making his grating codes available for this work, Matt Underhill for fabricating the gratings and David Thoen for helping with the surface profile measurements. EU RadioNet and TU Delft Space Institute are acknowledged for their supports. The work at MIT was supported by NASA. The work at Sandia was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration. Publisher Copyright: {\textcopyright} 2017, OSA - The Optical Society. All rights reserved.",
year = "2017",
month = nov,
day = "27",
doi = "10.1364/OE.25.029587",
language = "English (US)",
volume = "25",
pages = "29587--29596",
journal = "Optics Express",
issn = "1094-4087",
publisher = "The Optical Society",
number = "24",
}