The tell-tale signature of most lasers used in everyday applications—from bar-code scanners to pen-size pointers—is a bright red glow. The color is determined by the lights wavelength, and most lasers emit at only one wavelength. Now a new report published in the current issue of the journal Nature describes a light source measuring only tens of millimeters across that changes color according to temperature.
To make the new laser, Diederik Wiersma and Stefano Cavalieri of the European Laboratory for Non-linear Spectroscopy in Florence, Italy, manipulated the properties of a so-called random laser. Random lasers use light-diffusing material—often in the form of a fine powder—to trap light within the system long enough for amplification to occur. The more the light scatters, the larger the overall gain of the laser.
The researchers placed a liquid crystal inside a random laser source. By heating the crystal and changing the arrangement of its atoms, they could control the amount of light scattering within the laser and hence the color of emitted light. This so-called tunable random laser, the authors conclude, may one day find application as a source in active displays and temperature-sensitive screens or as a remote temperature-sensing device.
Sarah Graham | Scientific American
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DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.
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Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.
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Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.
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The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.
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Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.
"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...
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