Matter manipulation with extreme terahertz light: Progress in the enabling THz technology

TLDR

Terahertz light uniquely couples to low‑energy excitations, enabling the probing and control of quasi‑particles, phase transitions, and molecular rotations, and strong‑field few‑cycle pulses have opened the possibility of driving materials into novel dynamic states with properties distinct from equilibrium. This review systematically surveys existing studies on matter manipulation with strong‑field few‑cycle THz light and anticipates new results by examining how driving excitations can alter material properties and enable useful control of molecules and particles. The review evaluates roughly 200 recent studies, surveys state‑of‑the‑art strong‑field few‑cycle THz sources and their operation parameters, and examines techniques for guiding, focusing, reshaping, and diagnosing THz pulses.

Abstract

Terahertz (THz) light has proven to be a fine tool to probe and control quasi-particles and collective excitations in solids, to drive phase transitions and associated changes in material properties, and to study rotations and vibrations in molecular systems. In contrast to visible light, which usually carries excessive photon energy for collective excitations in condensed matter systems, THz light allows for direct coupling to low-energy (meV scale) excitations of interest. The development of light sources of strong-field few-cycle THz pulses in the 2000s opened the door to controlled manipulation of reactions and processes. Such THz pulses can drive new dynamic states of matter, in which materials exhibit properties entirely different from that of the equilibrium. In this review, we first systematically analyze known studies on matter manipulation with strong-field few-cycle THz light and outline some anticipated new results. We focus on how properties of materials can be manipulated by driving the dynamics of different excitations and how molecules and particles can be controlled in useful ways by extreme THz light. Around 200 studies are examined, most of which were done during the last five years. Secondly, we discuss available and proposed sources of strong-field few-cycle THz pulses and their state-of-the-art operation parameters. Finally, we review current approaches to guiding, focusing, reshaping and diagnostics of THz pulses.