The fastest optical microscope to date, 1,000 times more powerful than a conventional optical microscope, has been assembled by researchers at the University of Colorado, enabling them to probe and visualize matter at the atomic level with incredible speed.
The "image frame" rate captured by the team, which is led by CU physics professor Markus Raschke, is one trillion times faster than the blink of an eye. Researchers have used the microscope, the first of its kind, to make real-time, slow-motion movies of light interacting with electrons in nanomaterials.
According to Raschke, this marks the first time anyone has been able to probe matter on its natural time and length scale, imaging and measuring the motions of electrons in real space and time.
The CU researchers said a number of important processes such as photosynthesis, energy conversion and use, as well as biological functions, are based on the transfer of electrons and ions from molecule to molecule. They used a technique called "plasmonic nanofocusing" to focus extraordinarily short laser pulses into tiny bits of gold film matter through use of a nanometer-sized metal tip.
Raschke was traveling abroad this past week. But in an email, he said the microscopy with which the team is working has the capacity to focus a laser light to a spot smaller than any light has ever previously been focused on, at a spatial resolution "100 times better than conventional optical microscopes."
"Our study brings nanoscale microscopy to the next level, with the ability to capture detailed images evolving on extremely fast time scales," Vasily Kravtsov, a CU graduate student in physics and first author of the paper, stated in a news release.
The researchers' findings are addressed in a paper appearing in the Feb. 8 issue of Nature Nanotechnology.
In an email, Raschke explained the importance of the researchers' work by saying, "Electrons determine almost everything in materials. They make the chemical bond in molecules, they determine conductivity in metals, they are what you try to activate and build up an electrical potential to drive a current in a solar cell, or the inverse, when you charge a battery."
Therefore, he noted, understanding their behavior at the most elementary level — imaging their motion in space and time — is "the key to understanding and optimizing ... different materials and systems."
Raschke said that going forward, the experimental design of the instrument will be improved to make it suitable for more routine applications, but that it will also be applied to increasingly sophisticated science problems.
Other co-authors on the Nature Nanotechnology paper include CU postdoctoral researcher Ronald Ulbricht and former CU postdoctoral researcher Joanna Atkin, who is now on the faculty at the University of North Carolina-Chapel Hill.