Researchers at Texas A&M University have achieved what was once thought impossible – they created a device capable of compressing quantum fluctuations of light in a directed path and used it to improve image contrast.
This unique “flashlight” was built to increase the signal-to-noise ratio present in spectroscopic measurements of Brillouin microscopy, which visually record the mechanical properties of structures inside living cells and tissues. Test results reveal that the new source significantly increases image clarity and accuracy.
“This is a new avenue in research,” said Dr. Vladislav Yakovlev, associate professor in the College of Engineering’s Department of Biomedical Engineering. “We specifically design the light in such a way that it can improve contrast.”
“It is a new milestone in the capabilities of widely used Brillouin microscopy and imaging for biological systems,” said Dr. Girish Agarwal, University Distinguished Professor in the Department of Biological and Agricultural Engineering in the College of Agriculture and Life Sciences. “And it becomes part of an international effort to develop quantum sensors for various applications, such as brain imaging, mapping the structure of biomolecules, and exploring underground sources of oil and water by designing supersensitive gravimeters.”
A paper detailing the work was published in OPTICAL.
All instruments capable of capturing an image or image also capture signal distortions or noise in the process. Distortions can come from too much or too little light, and even brightness or color issues in the environment around the subject. Most noise is unnoticed until the image is enlarged enough for the unaided eye to clearly see the unwanted pixels.
Brillouin microscopy is the fundamental limit of currently possible small-scale measurement imaging. The process aims lasers at solid objects and measures the waves or vibrational signals produced by moving atoms and structures in visibly still material.
Noise produced on this scale can severely obscure incoming signals, creating cloudy images that are difficult to interpret. Currently, all laser spectroscopy systems, such as Brillouin microscopy, suffer from the natural and technical signal distortions associated with laser light, which is why newer light sources are needed.
Six years ago, Yakovlev tried to improve the signal-to-noise ratio in Brillouin microscopy using intense light sources. Unfortunately, overexposure to light damaged the cells he envisioned.
Yakovlev searched the literature for answers and found a theory from the 1980s that posited that quantum light could solve the problem, though it didn’t say how. Agarwal, an expert in quantum physics, came up with a possible way. Dr. Tian Li, then a postdoctoral researcher at the University of Maryland, was hired to create the first quantum light lab at Texas A&M. Laboratory space was provided by Dr. Marlan Scully, director of the Institute for Quantum Science and Engineering.
The team faced two significant challenges: finding funding for such a wild idea, and finding graduate students and postdoctoral researchers to help them—those who were willing to fall into the fields of biology and quantum physics.
After nearly two years of vigorous exploration, the device evolved into a table-sized device with complex optical configurations and measurement tools that allowed researchers to adjust, direct and manipulate and efficiently detect light. During that time, Li gained a better understanding of biology, and Yakovlev and Agarwal developed a mechanism to create the appropriate light state and matter needed to reduce noise without damaging living cells.
Although the light squeezer can be adopted for other spectroscopic measurements such as Raman scattering, Yakovlev and Agarwal improve the capabilities of Brillouin microscopy to identify viscous or elastic materials in biological systems. These systems control the physical properties of cells and cell structures and define everything from cell development to cancer progression.
Seeing the details clearly makes a huge difference in biomedical breakthroughs.
“Every time you get a new telescope or something like gravitational-wave astronomy, you discover new things that you can’t see without it,” Yakovlev said. “The same thing works in biology. Before the invention of the microscope, we didn’t know we were made up of individual cells.”
So far, only the contrast of the spectroscopic images has been improved, but Yakovlev and Agarwal are already working on Agarwal’s theory to improve the spatial resolution, or the smallest details possible. And if the task leads to the creation of another complex device that pushes the limits of current technology, researchers are ready and willing to do so.
“I like those kinds of projects where people tell you something will never work, and it does,” Yakovlev said. “I like challenges”.
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Tian Li et al., Quantum Stimulated Brillouin Scattering Spectroscopy and Imaging, OPTICAL (2022). DOI: 10.1364/OPTICA.467635
Provided by Texas A&M University College of Engineering
Citation: Quantum light source advances bio-imaging clarity (2022, September 19) Retrieved September 20, 2022, from https://phys.org/news/2022-09-quantum-source-advances-bio-imaging-clarity.html
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