Highly scalable multicycle THz production with a homemade periodically poled macrocrystal

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 similar to 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 similar to 300 mu m thick wafers. Each wafer is consecutively rotated by 180 degrees 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 similar to 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.