81 supra-THz beams generated by a Fourier grating and a quantum cascade laser
Name
oe-27-23-34192.pdf
Description
Published version
Size
3.95 MB
Format
Adobe PDF
Checksum (MD5)
f151b608bfaef13d2c857eaa636d1cbc
Author(s)
Khalatpour, Ali
Hu, Qing
Date Issued
November 2019
Journal
Optics Express
Publisher
The Optical Society
Citation
Gang, Yunger et al. “81 supra-THz beams generated by a Fourier grating and a quantum cascade laser.” Optics Express, 27, 23 (November 2019): 374460 © 2019 The Author(s)
Version
Final published version
Abstract
Large heterodyne receiver arrays (~100 pixel) allow astronomical instrumentations to map more area within limited space mission lifetime. One challenge is to generate multiple local oscillator (LO) beams. Here, we succeeded in generating 81 beams at 3.86 THz by combining a reflective, metallic Fourier grating with an unidirectional antenna coupled 3rd-order distributed feedback (DFB) quantum cascade laser (QCL). We have measured the diffracted 81 beams by scanning a single pyroelectric detector at a plane, which is in the far field for the diffraction beams. The measured output beam pattern agrees well with a simulated result from COMSOL Multiphysics, with respect to the angular distribution and power distribution among the 81 beams. We also derived the diffraction efficiency to be 94 ± 3%, which is very close to what was simulated for a manufactured Fourier grating (97%). For an array of equal superconducting hot electron bolometer mixers, 64 out of 81 beams can pump the HEB mixers with similar power, resulting in receiver sensitivities within 10%. Such a combination of a Fourier grating and a QCL can create an LO with 100 beams or more, enabling a new generation of large heterodyne arrays for astronomical instrumentation.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1364/OE.27.034192
