Electron microscopes have been around for almost a century, but a new record-breaking technique has finally delivered something physicists have been waiting for for decades: For the first time, a transmission electron microscope can see electrons with such clarity that they can see their individual components. Researchers believe they’ve opened up an entirely new field of optical science that they’re now calling “ato-microscopy,” with implications for the fields of quantum physics, biology, and chemistry.
The breakthrough was led by a team of experts from the University of Arizona and is detailed in a new study published on August 21. Scientific advancesMohammed Hassan, an associate professor of physics and optical sciences at the University of Arizona, likens a transmission electron microscope to a smartphone camera.
“When you buy the latest smartphone, it has a better camera,” Hassan said. Attached to the University Statement It was announced on Wednesday: “We hope that this microscope will enable the scientific community to understand the quantum physics behind the behaviour and movement of electrons.”
[Related: Winners of the 2023 Nobel Prize in physics measured electrons by the attosecond.]
on the other hand, The original electron microscope Arrived in the early 1930s (still controversial today) Inventor Since the 2000s, scientists have relied on instruments called transmission electron microscopes. In these instruments, objects are magnified and Millions of times That size is far beyond what optical microscopes can achieve, because it relies on pulses of electronic laser beams being fired at the object. From there, extremely precise camera sensors and lenses image these atomic particles as they pass through the sample. The change in the object observed between these images is called the time resolution of the microscope. To increase the resolution, researchers have looked at speeding up these laser bursts down to attoseconds, which are just one hundred trillionth of a second.
But once again, the problem is the plural of “attosecond.” If physicists want to freeze a single electron and study its incomprehensibly fast subatomic reactions and interactions in detail, they need a transmission electron microscope capable of firing single attosecond pulses. To achieve this, the researchers turned to work pioneered by the 2023 Nobel Prize winners in Physics, who generated the first extreme ultraviolet pulses also measured in attoseconds. Building on that foundation, the team finally achieved the one-attosecond benchmark.
To do so, the researchers developed and built a new microscope that splits a laser into a single electron pulse and two ultrashort light pulses. The first light pulse, called the pump pulse, energizes the sample’s electrons. Then, what’s called an optical gating pulse is initiated, providing an extremely small window of time during which a one-attosecond electron pulse is emitted from the microscope. Once the two ultrashort light pulses are properly synchronized, the operator can time the electron pulse to capture atomic events with attosecond-level time resolution.
“Improvements to time resolution in electron microscopes have been anticipated for a long time and have been the focus of many research groups,” Hassan said Wednesday. “… For the first time, we can see fragments of electrons in motion.”
According to the research summary, attosecond microscopy will enable physicists, optical scientists and other experts to study the movement of electrons in unprecedented detail and “directly link it to the structural dynamics of matter in real time and spatial domains,” which they hope will pave the way for “real-world attosecond science applications in quantum physics, chemistry and biology.”
