Highly scalable multicycle THz production with a homemade periodically poled macrocrystal

François Lemery,Ulrich Dorda,Thomas Vinatier,Bruno Lucas,Julien Demailly,Frank Mayet,Moana Pittman,Elsa Baynard,Alok-Kumar Pandey,Ralph Aßmann

doi:10.1038/s42005-020-00421-2

François Lemery, Ulrich Dorda + Show 8 more

Open Access

https://doi.org/10.1038/s42005-020-00421-2

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Abstract

The THz regime is widely appealing across many disciplines including solid-state physics, life sciences, and increasingly in particle acceleration. Multicycle THz pulses are typically formed via optical rectification in periodically poled crystals. However the manufacturing procedures of these crystals limit their apertures to below ~1 cm, which from damage limitations of the crystal, limits the total pump power which can be employed, and ultimately, the total THz power which can be produced. Here we report on the simple in-house fabrication of a periodically poled crystal using ~300 μm thick wafers. Each wafer is consecutively rotated by 180∘ to support quasi-phase matching. We validate the concept with a Joule-class laser system operating at 10 Hz and measure up to 1.3 mJ of energy at 160 GHz, corresponding to an average peak power of approximately 35 MW and a conversion efficiency of 0.14%. In addition, a redshifting of the pump spectrum of ~50 nm is measured. Our results indicate that high-power THz radiation can be produced with existing and future high-power lasers in a scalable way, setting a course toward multi-gigawatt multicycle THz pulses.

Highlights

The THz regime is widely appealing across many disciplines including solid-state physics, life sciences, and increasingly in particle acceleration
High-power single-cycle THz generation has flourished with the introduction of the tilted pulse front technique in lithium niobate (LN)[14,15,16]
The damage threshold of lithium niobate thereby limits the laser power which can be handled by the crystal, which inherently limits the production of high-power THz pulses

Summary

Introduction

The THz regime is widely appealing across many disciplines including solid-state physics, life sciences, and increasingly in particle acceleration. Multicycle THz radiation has been extensively studied, and can be produced with quasi-phase matching approaches in a periodically poled lithium niobate (PPLN)[17,18,19,20,21,22,23,24,25,26,27]. For high-power applications, the limited aperture sizes have motivated the development of wafer-bonded quasiphase matching crystals[32,33]. These fabrication techniques are challenging for large diameter wafers and require delicate in-vacuum procedures, limiting their widespread use

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