Ionizing terahertz waves with 260 MV/cm from scalable optical rectification.

Terahertz (THz) waves, known as non-ionizing radiation owing to their low photon energies, can actually ionize atoms and molecules when a sufficiently large number of THz photons are concentrated in time and space. Here, we demonstrate the generation of ionizing, multicycle, 15-THz waves emitted from large-area lithium niobate crystals via phase-matched optical rectification of 150-terawatt laser pulses. A complete characterization of the generated THz waves in energy, pulse duration, and focal spot size shows that the field strength can reach up to 260 megavolts per centimeter.

Terahertz Optical Properties and Carrier Behaviors of Graphene Oxide Quantum Dot and Reduced Graphene Oxide Quantum Dot via Terahertz Time-Domain Spectroscopy.

Graphene quantum dots (GQDs) with a band gap have been widely applied in many fields owing to their unique optical properties. To better utilize the optical advantages of GQDs, it is important to understand their optical characteristics. Our study demonstrates the optical properties and carrier behaviors of synthesized graphene oxide quantum dot (GOQD) and reduced graphene oxide quantum dot (rGOQD) pellets via Terahertz time-domain spectroscopy (THz-TDS).

Topological Surface-Dominated Spintronic THz Emission in Topologically Nontrivial Bi Sb Films.

Topological materials have significant potential for spintronic applications owing to their superior spin-charge interconversion. Here, the spin-to-charge conversion (SCC) characteristics of epitaxial Bi Sb films is investigated across the topological phase transition by spintronic terahertz (THz) spectroscopy. An unexpected, intense spintronic THz emission is observed in the topologically nontrivial semimetal Bi Sb films, significantly greater than that of Pt and Bi Se , which indicates the potential of Bi Sb for spintronic applications.

Transient Carrier Cooling Enhanced by Grain Boundaries in Graphene Monolayer.

Using a high terahertz (THz) electric field (E), the carrier scattering in graphene was studied with an electric field of up to 282 kV/cm. When the grain size of graphene monolayers varies from small (5 μm) and medium (70 μm) to large grains (500 μm), the dominant carrier scattering source in large- and small-grained graphene differs at high THz field, i.e.

Terahertz dynamic imaging of skin drug absorption.

Terahertz (THz) imaging is a nondestructive, label-free, rapid imaging technique which gives the possibility of a real-time tracing of drugs within the skin. We evaluated the feasibility of THz dynamic imaging for visualizing serial changes in the distribution and penetration of a topical agent, dimethyl sulfoxide (DMSO) containing ketoprofen, using excised mouse skins. THz imaging was performed for 6 h after drug application to the skin and was compared with the results obtained using the Franz cell diffusion test, a standard in vitro skin absorption test.