Large-area periodically-poled lithium niobate wafer stacks optimized for high-energy narrowband terahertz generation
Optics Express 31, 4041 (2023)
We investigate and optimize the THz emission from periodically-poled lithium niobate (PPLN) wafer stacks as a function of wafer number, pump fluence, pulse duration and chirp, wafer separation, and pump focusing. Using 135 µm-thick, 2 inch-diameter wafers we generate high-energy, narrowband THz pulses with central frequencies up to 0.39 THz, directly suitable for THz-driven particle acceleration applications.
Six-dimensional phase space preservation in a terahertz-driven multistage dielectric-lined rectangular waveguide accelerator
Phys. Rev. Accel. Beams 24, 121303 (2021)
We show how to mitigate transverse emittance and energy spread growth by using a staged accelerator, driven by terahertz (THz) frequency radiation pulses in a lattice with alternating orientation dielectric-lined waveguides and intervening matching optics, thereby opening a route to multistage THz linacs. We demonstrate the slice transverse emittance is conserved and the growth in the slice energy spread is reduced by 70%–80% simultaneously using two stages, with each providing an interaction length of 4 mm and an energy gain of up to 2 MeV.
Acceleration of relativistic beams using laser-generated terahertz pulses
Nature Photonics 14, 755 (2020)
We demonstrate acceleration of a relativistic electron beam in a THz-driven linear accelerator. Narrowband THz pulses were phase-velocity-matched with 35 MeV, 60 pC electron bunches, imparting multi-cycle energy modulation to chirped (6 ps) bunches and injection-phase-dependent energy gain (up to 10 keV) to sub-cycle (2 ps) bunches. These results establish a route to whole-bunch linear acceleration of sub-picosecond particle beams, directly applicable to scaled-up and multi-staged concepts capable of preserving beam quality.
Demonstration of sub-luminal propagation of single-cycle terahertz pulses for particle acceleration
Nature Communications. 8, 421 (2017)
We describe and demonstrate a method for generating single-cycle terahertz pulses that propagate with an effective sub-luminal phase velocity, and without distortion during propagation. This novel travelling source approach fulfils the requirement for a sub-luminal phase velocity in laser-driven particle acceleration schemes without the need for dispersive structures or waveguides to extend the field-particle interaction.
Dispersion in dielectric-lined waveguides designed for terahertz-driven deflection of electron beams
Applied Physics Letters 118, 144102 (2021)
We have developed dielectric-lined rectangular waveguide structures for THz-driven ultrafast deflection of 100 keV electron beams. The structures were designed to achieve THz phase velocity matching with co-propagating electron bunches. The phase-matching capability was experimentally confirmed through time-frequency analysis of the broadband coherent THz transmission measured by electro-optic sampling. We determined the propagation constants for both the dielectric-lined waveguide structure and the integrated input coupling horn.
Longitudinally polarized single-cycle terahertz pulses generated with high electric field strengths
Applied Physics Letters. 108, 221102 (2016)
By using a matched pair of polarity inverted MgO:SLN crystals as an optical rectification source, we demonstrate the generation of strong on-axis longitudinally polarized single-cycle terahertz radiation, with electric field amplitudes in excess of 11 kV/cm. In contrast to segmented waveplate sources, the single-cycle terahertz temporal profile is maintained hence maximizing the attainable electric field strength.