Ytterbium-laser-driven THz generation in thin lithium niobate at 1.9 kW average power in a passive enhancement cavity

Suerra, Edoardo; Canella, Francesco; Giannotti, Dario; Khalili, Mohsen; Wang, Yicheng; Hasse, Kore; Suntsov, Sergiy; Kip, Detlef; Saraceno, Clara; Cialdi, Simone; Galzerano, Gianluca

doi:10.1063/5.0252040

Ytterbium-laser-driven THz generation in thin lithium niobate at 1.9 kW average power in a passive enhancement cavity

Publication date

2025-04-16

Document type

Forschungsartikel

Author

Suerra, Edoardo

Canella, Francesco

Giannotti, Dario

Khalili, Mohsen

Wang, Yicheng

Hasse, Kore

Suntsov, Sergiy

Kip, Detlef

Saraceno, Clara

Cialdi, Simone

Galzerano, Gianluca

Organisational unit

Experimentalphysik und Materialwissenschaften

DOI

10.1063/5.0252040

URI

https://openhsu.ub.hsu-hh.de/handle/10.24405/21319

Publisher

AIP Publishing

Series or journal

APL Photonics

ISSN

2378-0967

Periodical volume

10

Periodical issue

4

Article ID

046111

Peer-reviewed

✅

Part of the university bibliography

✅

Language

English

Abstract

Single-cycle, high-power, high-repetition-rate THz pulse sources are becoming the cornerstone of several scientific and industrial applications. A promising and versatile method for high-power THz generation is optical rectification in nonlinear crystals pumped by powerful near-infrared ultrafast laser systems. In this context, ytterbium-based laser sources are particularly advantageous in terms of power scalability and technology establishment. However, as the repetition rate increases toward hundreds of MHz, the conversion efficiency typically decreases, as most laser systems do not reach sufficiently high average powers to correspondingly enhance the peak power to drive the nonlinear conversion process efficiently. An alternative approach to achieving a sufficiently high average power at a high repetition rate is based on passive enhancement cavities, which boost the pulse energy of standard watt-level ytterbium lasers by orders of magnitude. We present the first demonstration of optical rectification in a passive enhancement cavity at multi-kW levels, achieved by a 240-fold power enhancement. By irradiating a 50-μm thin lithium niobate plate with 1.9-kW average power inside the enhancement cavity, we generate milliwatt-level THz pulses with 2-THz bandwidth and 93-MHz repetition rate, mostly limited by the driving pulse duration. To the best of our knowledge, this represents the highest driving average power used for optical rectification. This methodology represents a promising new step toward high-repetition-rate and high average power single-cycle THz sources using widely available multi-watt level Yb lasers.

Description

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