Ultrabroadband Gain-Switched and Superluminescent Terahertz Semiconductor Lasers

Fuente: arXiv
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Main Authors: Senica, Urban, Schreiber, Michael A., Beck, Mattias, Jirauschek, Christian, Faist, Jérôme, Scalari, Giacomo
Format: Preprint
Published: 2026
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_version_ 1866913062739509248
author Senica, Urban
Schreiber, Michael A.
Beck, Mattias
Jirauschek, Christian
Faist, Jérôme
Scalari, Giacomo
author_facet Senica, Urban
Schreiber, Michael A.
Beck, Mattias
Jirauschek, Christian
Faist, Jérôme
Scalari, Giacomo
contents Terahertz quantum cascade lasers (THz QCLs) are chip-scale semiconductor lasers operating in the frequency range between 1-6 THz, useful as compact sources for spectroscopy, communications, and non-destructive imaging and testing. Here, we apply low-frequency microwave modulation on a planarized THz QCL to generate ultrabroadband emission in the THz range. For very low modulation frequencies below 1 GHz, a gain-switched octave-spanning spectrum with a smooth spectral envelope is generated between 1.9 - 4.1 THz. Increasing the modulation frequency broadens the lasing modes until a low-coherence, continuous emission spectrum is achieved in the superluminescent regime, covering the spectral region between around 3 - 4 THz, without any discrete lasing modes or spectral gaps. We complement the experimental results with extensive analytical models and numerical simulations that capture the intracavity laser dynamics and fully explain the different operation regimes. These devices could prove useful for absorption spectroscopy without any spectral gaps, and as ultrabroadband sources of THz radiation.
format Preprint
id arxiv_https___arxiv_org_abs_2604_23499
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Ultrabroadband Gain-Switched and Superluminescent Terahertz Semiconductor Lasers
Senica, Urban
Schreiber, Michael A.
Beck, Mattias
Jirauschek, Christian
Faist, Jérôme
Scalari, Giacomo
Optics
Terahertz quantum cascade lasers (THz QCLs) are chip-scale semiconductor lasers operating in the frequency range between 1-6 THz, useful as compact sources for spectroscopy, communications, and non-destructive imaging and testing. Here, we apply low-frequency microwave modulation on a planarized THz QCL to generate ultrabroadband emission in the THz range. For very low modulation frequencies below 1 GHz, a gain-switched octave-spanning spectrum with a smooth spectral envelope is generated between 1.9 - 4.1 THz. Increasing the modulation frequency broadens the lasing modes until a low-coherence, continuous emission spectrum is achieved in the superluminescent regime, covering the spectral region between around 3 - 4 THz, without any discrete lasing modes or spectral gaps. We complement the experimental results with extensive analytical models and numerical simulations that capture the intracavity laser dynamics and fully explain the different operation regimes. These devices could prove useful for absorption spectroscopy without any spectral gaps, and as ultrabroadband sources of THz radiation.
title Ultrabroadband Gain-Switched and Superluminescent Terahertz Semiconductor Lasers
topic Optics
url https://arxiv.org/abs/2604.23499