Researchers at the University of Boulder have advanced the field of ptychography by innovating a new imaging method using donut-shaped light beams. This technique enables detailed imaging of small regularly patterned structures such as semiconductors, overcoming previous limitations of conventional microscopy. This advance promises significant improvements in nanoelectronics and biological imaging. (Artist’s concept) Credit: SciTechDaily.com
In a new study, researchers at the University of Boulder used a donut-shaped beam of light to take detailed images of objects too small to be seen with traditional microscopes.
Advances in Nanoelectronic Imaging
This new technology could help scientists improve the inner workings of a variety of ‘nanoelectronics’, including miniature ones. The semiconductor inside a computer chip. This discovery was featured in a special issue on December 1st. Optics and Photonics News called Optics in 2023.
Ptychography: A Lens into the Microscopic World
This research is the latest advance in the field of ptychography, a challenging yet powerful technique for seeing very small things. Unlike traditional microscopes, ptychography tools do not directly observe small objects. Instead, it shines a laser at a target and measures how the light is scattered. This is a bit like making shadow puppets on a wall when viewed through a microscope.
A scattering pattern produced by donut-shaped rays of light reflecting off an object with a regularly repeating structure. Credit: Wang et al., 2023, optica
Overcoming Ptychography Challenges
So far, the approach has worked surprisingly well, with one major exception, said Margaret Mahne, the study’s lead author and distinguished professor of physics.
“Until recently, we had been completely unsuccessful with highly periodic samples or objects with regularly repeating patterns,” says the UW-Boulder and National Institute of Standards and Technology (NIST) collaboration. Margaret, a fellow at JILA, said, “That’s a problem because this has a lot of nanoelectronics in it.”
She pointed out that many important technologies, such as some semiconductors, are made up of atoms such as silicon and carbon bonded in regular patterns, like small grids or meshes. So far, it has proven difficult for scientists to observe these structures up close using ptychography.
Donut-shaped beams of light scatter from incredibly small structures. Credit: Wang et al., 2023, optica
A Breakthrough in Donut-Shaped Light
But in a new study, Murunet and colleagues have come up with a solution. Instead of using a traditional laser in a microscope, they generated a donut-shaped beam of extreme ultraviolet light.
The researchers’ new approach can collect precise images of small, delicate structures that are around 10 to 100 nanometers in size, or many times smaller than a millionth of an inch. In the future, researchers expect to be able to zoom in and observe even smaller structures. The donut beam, or angular momentum beam of light, also does not damage small electronic equipment during the process, as existing imaging tools such as electron microscopes do.
“In the future, this method could be used to inspect polymers used in semiconductor manufacturing and printing for defects without damaging the structure during the process,” Mahne said. Stated.
Bin Wang and Nathan Brooks, who received their PhDs from JILA in 2023, are the lead authors of this new study.
Pushing the Limits of Microscopy
Mahne said this research pushes the fundamental limits of microscopy. Because of the physics of light, lens-based imaging tools can only see the world to a resolution of about 200 nanometers, which is not precise enough to capture many viruses. For example, those that infect humans. Although scientists can freeze viruses to death and view them with powerful cryo-electron microscopes, they still cannot capture the activity of these pathogens in real time.
Ptychography, developed in the mid-2000s, could help researchers break through that limit.
How ptychography works
To understand how, go back to shadow puppets. Imagine that a scientist wants to collect stylized images of very small structures, perhaps the letters that spell “CU.” To do this, they first shine a laser beam on the text and scan the text multiple times. When light hits “C” and “U” (in this case the dolls), the light rays break and scatter, creating a complex pattern (shadow). Scientists record those patterns using sensitive detectors and analyze them using a series of mathematical formulas. Given enough time, they will perfectly recreate the shape of the doll from the shadow it casts, Mahne explained.
Evolution to Finer Details
Stated. Bin Wang and Nathan Brooks, who received their PhDs from JILA in 2023, are the lead authors of this new study. Other co-authors of the new study include physics professor and JILA fellow Henry Kaptein, current and former JILA graduate students Peter Johnsen, Nicholas Jenkins, Yuka Esashi, Iona Binney, Includes Michael Tanksalvara.
Reference: “High-fidelity ptychographic imaging of highly periodic structures enabled by vortex harmonic beams” Michael Tanksalvala, Henry C. Kapteyn, Bin Wang, Peter Johnsen, Yuka Esashi, Iona Binnie, Margaret M. Murnane, Nicholas W. Jenkins, and Nathan J. Brooks, September 19, 2023, optica.
DOI: doi:10.1364/OPTICA.498619
Source: scitechdaily.com
