Molecular light transformer: seeing what you couldn't see before
Researchers from several European universities and the Chinese Wuhan Institute of Technology have developed a new method to detect light in the deep infrared range by using it frequency convert into that of visible light. The device can see the "field of view" of sensitive detectors for visible light up into the Infrared range expand. The discovery, described as groundbreaking, was made in the magazine Science published.
Frequency changeover is not an easy task. Because of the Conservation of energy the frequency of light is a fundamental property that cannot easily be changed by reflecting light off a surface or directing it through a material. At lower frequencies, the energy transported by light is insufficient to generate the Photoreceptors to activate in our eyes and in many sensors, which is a problem, since a lot takes place in the frequency range below 100 THz, ie in the mid and far infrared. For example, a body with a surface temperature of 20 ° C emits infrared light with frequencies of up to 10 THz, which can be "seen" with the help of thermal imaging. In addition, chemical and biological substances have pronounced absorption bands in the mid-infrared range, which means that we can use them with the help of the infraredspectroscopy identify non-destructively.
Scientists have solved this problem by using the Infrared light with the help of an intermediate medium - small oscillating particles - added energy. The infrared light is directed onto the molecules, where it is converted into vibrational energy. At the same time they become the same molecules from a higher frequency laser beam that provides additional energy and converts the vibrations into visible light. To improve the conversion process, the molecules are embedded between metallic nanostructures that act as optical antennas and infrared light and laser energy focus on the molecules.