81 supra-THz beams generated by a Fourier grating and a quantum cascade laser

Gan, Y., Mirzaei, B., Silva, J. R. G., Khalatpour, A., Hu, Q., Groppi, C., Siles, J., van der Tak, F. & Gao, J-R., 11-Nov-2019, In : Optics Express. 27, 23, p. 34193-34204 12 p.

Research output: Contribution to journalArticleAcademicpeer-review

Large heterodyne receiver arrays (similar to 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. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Original languageEnglish
Pages (from-to)34193-34204
Number of pages12
JournalOptics Express
Issue number23
Publication statusPublished - 11-Nov-2019



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