Broadband Two-Dimensional Far-Field Beam Profiling of Commercial CW Terahertz Photomixers from 0.2 to 1.5 THz

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Hauptverfasser: Kristensen, Mathias Hedegaard, Skovsen, Esben
Format: Preprint
Veröffentlicht: 2025
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author Kristensen, Mathias Hedegaard
Skovsen, Esben
author_facet Kristensen, Mathias Hedegaard
Skovsen, Esben
contents We present a systematic far-field characterization of four commercial PIN diode terahertz photomixers over the 0.2-1.5 THz frequency range using a two-dimensional (2D) raster scanning method. The emission pattern of each transmitter, equipped with an integrated hyper-hemispherical silicon lens, was characterized using a broadband Schottky diode receiver over a 35 mm x 35 mm grid grid. The results reveal consistent frequency-dependent beam divergence and the emergence of distinct Airy diffraction patterns at intermediate frequencies, attributed to lens-induced aperture effects. In addition to qualitative mapping, we extract quantitative metrics -- including divergence slope, beam asymmetry, ellipticity, and centroid variability -- that enable objective comparison of beam profiles across devices and frequencies. This comprehensive mapping underscores the importance of full 2D beam profiling for understanding THz propagation and offers insights into lens design and photomixer packaging for optimized system performance.
format Preprint
id arxiv_https___arxiv_org_abs_2505_07136
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Broadband Two-Dimensional Far-Field Beam Profiling of Commercial CW Terahertz Photomixers from 0.2 to 1.5 THz
Kristensen, Mathias Hedegaard
Skovsen, Esben
Optics
Applied Physics
We present a systematic far-field characterization of four commercial PIN diode terahertz photomixers over the 0.2-1.5 THz frequency range using a two-dimensional (2D) raster scanning method. The emission pattern of each transmitter, equipped with an integrated hyper-hemispherical silicon lens, was characterized using a broadband Schottky diode receiver over a 35 mm x 35 mm grid grid. The results reveal consistent frequency-dependent beam divergence and the emergence of distinct Airy diffraction patterns at intermediate frequencies, attributed to lens-induced aperture effects. In addition to qualitative mapping, we extract quantitative metrics -- including divergence slope, beam asymmetry, ellipticity, and centroid variability -- that enable objective comparison of beam profiles across devices and frequencies. This comprehensive mapping underscores the importance of full 2D beam profiling for understanding THz propagation and offers insights into lens design and photomixer packaging for optimized system performance.
title Broadband Two-Dimensional Far-Field Beam Profiling of Commercial CW Terahertz Photomixers from 0.2 to 1.5 THz
topic Optics
Applied Physics
url https://arxiv.org/abs/2505.07136