American scientists used a highly efficient probe to superfocus white light into a spot
Scientists have developed new materials fornext generation electronics. They are so tiny that they don't reflect enough light, making it impossible to see fine colored details. Even the most powerful optical microscopes do not help. For example, under an optical microscope, carbon nanotubes appear grayish. This makes it difficult for scientists to study their unique properties and find ways to improve them for industrial use.
Researchers at the University of California atRiverside describes a revolutionary imaging technology that compresses lamp light into a nanometer-sized spot. This helps bring out previously invisible details, including colors. The technology, which improves the resolution of color images to an unprecedented level of 6 nm, will help scientists see nanomaterials in enough detail to make them more useful in electronics and other applications.
Ming Liu and Ruoxue Yang, assistant professors in the College of EngineeringMarlana and Rosemary Bourne at the University of California, Riverside used superfocus techniques to develop a unique tool. The method has already been used in previous work by scientists to observe vibrations of molecular bonds with a spatial resolution of 1 nanometer without the need for any focusing lens.
Now scientists have modified the instrument formeasurements of signals covering the entire visible wavelength range. It can be used to convey color and image of the electronic stripe structures of an object, not just molecular vibrations. The instrument compresses light from a tungsten lamp into silver nanowires with almost zero scattering or reflection. There, light on the surface of silver is carried by a vibrational wave of free electrons.
As a result, the condensed light leavesa silver nanowire tip with a radius of only 5 nm, along a conical path, like a beam of light from a flashlight. When the tip passes over an object, its effect on the shape and color of the beam is detected and recorded.
“This is similar to how a person uses a largefinger to control the spray of water from the hose - the scientists explain. "You know how to get the desired spray pattern by changing the position of your thumb, and similarly, in the experiment, we read the light pattern to extract the details of the object blocking the 5 nm light nozzle."
The light is then focused into a spectrometer where itforms a tiny ring shape. By scanning an area with a probe and recording two spectra for each pixel, researchers can formulate absorption and scatter images using colors. The initially grayish carbon nanotubes become colored, each with its own color.
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