By Patricia Daukantas
Optical tweezers with force-feedback, nanoscale lasers and cloud-level wind measurements from ground level are among the many topics featured in OSA’s peer-reviewed journals over the last few months.
A collaboration of scientists based in France, Scotland and England devised the low-cost optical tweezers, which appeared in the June 8 issue of Optics Express. The combination of a high-speed video camera and an inexpensive haptic interface gives the tweezers’ operator a “feel” for the two-dimensional forces being exerted on a 5-µm-diameter bead in a laser trap. According to a recent Laser Focus World article, the researchers will try to expand the force-feedback into the third dimension. The original OE article, which also appears in the Virtual Journal for Biomedical Optics, comes with a couple of QuickTime movie files showing the forces on the bead as it moves around.
Also writing in Optics Express, a group from Arizona State University (U.S.A.) and Technical University of Eindhoven (the Netherlands) reported lasing in tiny, semiconductor-filled metal-insulator-metal waveguides. The team used an innovative combination of semiconductors and metals, such as gold and silver, to get around the so-called diffraction limit.
Two scientists from the University of Hawaii (U.S.A.) have used ground-based stereo cameras to derive wind speeds in the upper (cloud) layers of the troposphere. According to their article in the August 15th Optics Letters, the pair captured cloud features on successive images taken with specially calibrated cameras set about 150 m apart at the Mauna Loa Observatory. From these images they derived wind speed and direction with errors of generally less than 10 percent for clouds 2 km in altitude.
Every month, OSA’s journals publish hundreds of other articles on optical communications, lasers, spectroscopy, geometrical optics, imaging, metrology, device physics, vision and more. For highlights of the latest content, check out OSA’s new feature, Spotlight on Optics, on Optics InfoBase.