Generation of THz radiation through molecular modulation in hydrogen-filled hybrid anti-resonant fibers

Fuente: arXiv
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Main Authors: Loranger, Sebastien, Jafari, Foroogh, Zubia, Joseba, Novoa, David
Format: Preprint
Published: 2023
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author Loranger, Sebastien
Jafari, Foroogh
Zubia, Joseba
Novoa, David
author_facet Loranger, Sebastien
Jafari, Foroogh
Zubia, Joseba
Novoa, David
contents We study the generation of narrowband terahertz (THz) pulses by stimulated Raman scattering and molecular modulation in hydrogen-filled hybrid hollow-core fibers. Using a judicious combination of materials and transverse structures, this waveguide design enables simultaneous confinement of optical and THz signals with reasonably low attenuation, as well as high nonlinear overlap. The THz pulses are then generated as the second Stokes band of a ns-long near-infrared pump pulse, aided by Raman coherence waves excited in the gaseous core by the beat-note created by the pump and its first Stokes band. Optimization of the fiber characteristics facilitates phase matching between the corresponding transitions and coherence waves while avoiding coherent gain suppression, resulting in optical-to-THz conversion efficiencies up to 60%, as confirmed by rigorous numerical modelling under ideal conditions. When the current optical material constraints are considered, however, the attainable efficiencies relax to 0.2%, a still competitive value compared to other systems. The approach is in principle power and energy scalable, as well as tunable in the 1 - 10 THz range without any spectral gaps, thereby opening new pathways to the development of fiber-based THz sources complementary to other mature technologies such as quantum cascade lasers.
format Preprint
id arxiv_https___arxiv_org_abs_2310_15346
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Generation of THz radiation through molecular modulation in hydrogen-filled hybrid anti-resonant fibers
Loranger, Sebastien
Jafari, Foroogh
Zubia, Joseba
Novoa, David
Optics
We study the generation of narrowband terahertz (THz) pulses by stimulated Raman scattering and molecular modulation in hydrogen-filled hybrid hollow-core fibers. Using a judicious combination of materials and transverse structures, this waveguide design enables simultaneous confinement of optical and THz signals with reasonably low attenuation, as well as high nonlinear overlap. The THz pulses are then generated as the second Stokes band of a ns-long near-infrared pump pulse, aided by Raman coherence waves excited in the gaseous core by the beat-note created by the pump and its first Stokes band. Optimization of the fiber characteristics facilitates phase matching between the corresponding transitions and coherence waves while avoiding coherent gain suppression, resulting in optical-to-THz conversion efficiencies up to 60%, as confirmed by rigorous numerical modelling under ideal conditions. When the current optical material constraints are considered, however, the attainable efficiencies relax to 0.2%, a still competitive value compared to other systems. The approach is in principle power and energy scalable, as well as tunable in the 1 - 10 THz range without any spectral gaps, thereby opening new pathways to the development of fiber-based THz sources complementary to other mature technologies such as quantum cascade lasers.
title Generation of THz radiation through molecular modulation in hydrogen-filled hybrid anti-resonant fibers
topic Optics
url https://arxiv.org/abs/2310.15346