Synopsis: Powering Up Terahertz Sources

A laser-based scheme generates short pulses of terahertz radiation with peak power close to a gigawatt.
Synopsis figure
Courtesy Amrutha Gopal/Friedrich Schiller University Jena

Terahertz (THz) radiation—the band of frequencies falling between the microwave and visible range—can pass through materials that block light and couple to important rotational, vibrational, or electronic degrees of freedom of solids and molecules. Many applications could take advantage of these properties, from wireless communications to imaging of biomolecules or semiconductor wafers. But a key stumbling block for THz technologies is the development of sufficiently powerful sources. Now, as reported in Physical Review Letters, Amrutha Gopal at the Friedrich Schiller University Jena, Germany, and co-workers have demonstrated a laser-based source that emits short THz pulses with the highest peak power ever recorded in a laboratory.

Presently, the most powerful THz sources are at expensive, large-scale accelerator facilities, which generate THz radiation by bending a beam of relativistic electrons with a magnet. Gopal et al.’s solution instead exploits a high-power laser available at the Friedrich Schiller University Jena. The authors focus the laser’s femtosecond pulses onto micrometer-thick metallic foils. The intense pulses ionize the material, creating hot plasma that emits THz radiation. The setup delivers ten THz pulses per second with a broad spectrum (0.330 THz). Since the energy is concentrated in pulses only about half a picosecond long, their peak power is close to a gigawatt.

The scheme also generates a synchronous beam of energetic ions, which suggests an intriguing medical application: the THz beam could be used for detecting cancerous cells on human skin (which reflect THz wavelengths differently than normal cells), while the ions could be directed selectively at such cells for simultaneous treatment. – Matteo Rini


Announcements

More Announcements »

Subject Areas

OpticsMaterials Science

Previous Synopsis

Soft Matter

Branching Out

Read More »

Next Synopsis

Atomic and Molecular Physics

Molecular Memory for Light

Read More »

Related Articles

Synopsis: Position Detector Approaches the Heisenberg Limit
Quantum Physics

Synopsis: Position Detector Approaches the Heisenberg Limit

The light field from a microcavity can be used to measure the displacement of a thin bar with an uncertainty that is close to the Heisenberg limit. Read More »

Focus: Complex Crystals Form from Heterogeneous Particles
Materials Science

Focus: Complex Crystals Form from Heterogeneous Particles

A suspension containing particles with wide-ranging diameters can crystallize into multiple ordered structures. Read More »

Synopsis: Glassy Fingerprints
Condensed Matter Physics

Synopsis: Glassy Fingerprints

The local structure of glasses and other disordered materials could be extracted from diffraction patterns, according to a proposal for a new technique. Read More »

More Articles