Highly scalable multicycle THz production with a homemade periodically poled macrocrystal

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.

Terahertz waveform synthesis in integrated thin-film lithium niobate platform

“…Also, the control of the waveguide dispersion by the geometry of the waveguides may be explored to achieve pulse compression and Fourier-limited pump pulses locally in the generation region, potentially increasing the generation efficiency and the spectral bandwidth of the signal generated by optical rectification up to several THz 46 . The concept of distributed pulse phase matching may be further explored in combination with periodic poling [47][48][49][50] and group delay engineering to synthesize arbitrary patterns of THz radiation by decomposition into temporal modes 51 . Here, pump pulses at other frequencies than the telecom may also be considered toward improved confinement of the probe and terahertz beam, e.g., at wavelengths of titanium sapphire lasers.…”

Terahertz waveform synthesis from integrated lithium niobate circuits

“…The latter may be explored to achieve pulse compression and Fourier-limited pump pulses locally in the generation region, thereby increasing the generation efficiency and the spectral bandwidth of the signal generated by optical rectification up to several THz [37]. The concept of distributed pulse phase matching may be further explored in combination with periodic poling [38][39][40][41] and group delay engineering to synthesise arbitrary patterns of THz radiation by a decomposition into temporal modes [42]. Finally, we note that LN circuits are ideal candidates also for THz metrology [12,43] where femtosecond pulses in the near-infrared could enable a sub-cycle resolution of the electric field of THz signals and have already proven extremely resourceful for quantum applications by characterization of quantum states of light through their sub-cycle electric field signatures [44,45].…”

Parameter dependencies in multicycle THz generation with tunable high-energy pulse trains in large-aperture crystals

“…Despite dedicated efforts to improve the performance of laser-driven multicycle THz sources, they still suffer from opticalto-terahertz conversion efficiencies below one percent, making it challenging to reach mJ-level pulse energies [4][5][6][7][8][9][10][11][12][13][14][15]. In order to increase conversion efficiencies, sophisticated ideas have been developed based on tailoring the spectrum and the temporal shape of the pump laser pulses.…”