Follow the links to read the full papers in the IET Digital Library.
Let's twist again
A temperature and strain insensitive high-birefringent fibre Bragg grating torsion sensor has been demonstrated by researchers in China. The work offers new theories and methods for twist sensing and can be used for monitoring the condition of, for example, bridges or buildings and other structures.
Combing the skies
Frequency-combs at high repetition rate will form a key part of the architecture of future astronomical instruments within major projects such as the Extremely Large Telescope. Researchers in the UK, Germany and China have shown that optical parametric oscillator combs have potential as suitable sources in this context by reporting the highest pulse repetition rate via Fabry-Perot mode filtering.
Researchers in Germany have applied an intracavity dispersion management method to a master oscillator power amplifier laser system. By fine-tuning the oscillator, they were able to generate 158 fs pulses, which is not only shorter than the pulses in their previous work but also shorter than the old record value for such a laser system.
A method to distribute magnetic flux uniformly and improve energy density for inductors with core enclosing winding is presented in work from the US. The work extends the ‘constant-flux’ concept previously applied to inductor geometries with core enclosed by windings. The method is demonstrated to halve the volume required compared to an equivalent commercial inductor.
In vivo demonstration of a microphone implantation technique for hearing aids that avoids skin movement problems is presented by researchers in Korea. They propose mounting the microphone in a hole drilled to the middle ear cavity. The screw-shaped package also does not attach to the ossicular chain making it less sensitive to feedback.