Watch any TV medical drama and you’ll see a defibrillator in action. During tense moments, defibrillators bring patients back from the brink of death with a dramatic shock. But what you don’t see on TV is the cell membrane, muscle, and skin damage that a defibrillator’s shock can cause. Even implanted defibrillators are painful to patients and damaging to tissue. But gentler devices may be on the way. A research team led by Stefan Luther of the Max Planck Institute and Flavio Fenton of Cornell University has found a new approach that greatly reduces the intensity of defibrillating shocks.
JILA researchers have developed a laser-based source of terahertz radiation that is unusually efficient and less prone to damage than similar systems. The technology might be useful in applications such as detecting trace gases or imaging weapons in security screening.
JILA instrument for generating terahertz radiation. Ultrafast pulses of near-infraredlaser light enter through the lens at left, striking a semiconductor wafer studded with electrodes (transparent square barely visible under the white box connected to orange wires) bathed in an oscillating electric field. The light dislodges electrons, which accelerate in the electric field and emit waves of terahertz radiation. At right is a close-up of the electron source.
Acoustic wave devices have been in commercial use for more than 60 years. The telecommunications industry is the largest consumer, accounting for ~3 billion acoustic wave filters annually, primarily in mobile cell phones and base stations.
These are typically surface acoustic wave (SAW) devices, and act as bandpass filters in both the radio frequency and intermediate frequency sections of the transceiver electronics. Several of the emerging applications for acoustic wave devices as sensors may eventually equal the demand of the telecommunications market.
