A revolutionary breakthrough in microscopy was recently announced by scientists at Lawrence Livermore National Laboratory (LLNL). Scientist Ted Laurence explains the world’s first 3D quantum ghost imaging microscope. Scientists Audrey Eshun (L) and Ted Laurence (R) This revolutionary device employs entangled photons to build high-resolution three-dimensional images of nanoparticles. This innovative technology holds promise for a range of applications in materials science and biology, allowing researchers to analyze structures at unprecedented detail.
The 3D quantum ghost imaging microscope operates by harnessing the unique properties of entangled photons. In the experiment, a laser is aimed at a beta barium borate crystal to generate pairs of entangled photons. One of these photons, which we refer to as the “signal” photon, goes straight towards the sample. Its entangled partner, referred to as the “idler” photon, goes directly to a detector. This two-pronged strategy empowers the microscope to amass a wealth of information about the sample being observed. Consequently, it increases sensitivity and delivers extensive data without requiring direct observation.
How the Microscope Works
The sample is mounted at a 45 degree angle with respect to the incoming signal photons. As these photons interact with the nanoparticles, in our work primarily silver nanoclusters, they scatter. The microscope uses a third objective lens to capture these scattered photons and focuses them into a second detector.
With meticulousness, researchers can determine spatial information down to the micron scale by analyzing the arrangement of emitted photons. Each side of the 3D cubes or voxels employed in this imaging method are only 40 micrometers across. Now, scientists are able to more faithfully reconstruct high-resolution images of intricate structures in three dimensions. This is again enabled by being able to record data in three spatial dimensions.
“This microscope is the first of its kind.” – Ted Laurence
The possibilities for such technology are endless. Yet it is the unique imaging capabilities that are pushing leading-edge developments across many scientific fields. For example, their in-depth observations helped researchers better understand chemical bonding and electronic band structure.
Advantages of Quantum Ghost Imaging
One of the most impactful advances provided by this new microscope will be its ability to acquire information with unprecedented sensitivity. With conventional imaging methods, we typically have to scan a sample and reconstruct an image. As Eshun understands, this process takes away the need for that need.
“This is a new way of 3D imaging that can do things with more sensitivity and gather more information without having to scan a sample.” – Audrey Eshun
Beyond time savings, the effective use of this method greatly decreases the risk of damage to sensitive, irreplaceable samples while they are being analyzed. At the same time, the ghost imaging technique provides a totally fresh way of thinking about how to visualize objects.
“Ghost imaging is like a game of Battleship. Instead of seeing an object directly, scientists use entangled photons to remove the background and reveal its silhouette.” – Audrey Eshun
This unique approach makes it easier for researchers to isolate features of interest in their samples, compared to conventional imaging methods.
Detailed Imaging Capabilities
The 3D quantum ghost imaging microscope affords a greatly improved approach to volumetric reconstruction of individual nanoparticles. By measuring the times of arrival of the entangled photons, scientists are able to find the x, y and z coordinates for each photon. This data can then be translated to digital models to produce incredibly detailed three-dimensional renderings of the space.
“By grouping all the photons that have the same timestamp, we can figure out the x, y and z position for each photon. These coordinates can then be plotted to form a 3D image.” – Audrey Eshun
This advanced, yet complex, process produces three-dimensional reconstructions that help scientists better understand the spatial orientation and positional behavior of nanoparticles in a sample. This new capability will open new frontiers for more advanced interdisciplinary research, including in nanotechnology, biomedicine, and other fields.