Engineers and students at Brown University have developed a new imaging technique called Quantum Multi-Wavelength Holography, which utilizes quantum entanglement to capture high-fidelity 3D images of microscopic objects. This method employs infrared light to illuminate targets and uses visible light, entangled with the infrared probe, to create images. By capturing both the intensity and phase of light, the technique produces true holographic images that accurately represent the depth of contours in objects.
Traditional imaging methods, such as X-rays or photographs, rely on capturing light reflected off objects. In contrast, quantum imaging leverages the phenomenon of quantum entanglement, where two photons become linked, and actions on one instantaneously affect the other, regardless of distance. In this approach, an 'idler' photon scans the target object, while a 'signal' photon, entangled with the idler, is detected to form the image.
The researchers demonstrated this technique by creating a holographic image of a test object—a metal letter 'B' approximately 1.5 millimeters in diameter. This successful demonstration serves as a proof-of-concept for generating high-fidelity 3D images using quantum entanglement.
By employing infrared light for probing and visible light for detection, the method offers significant advantages. Infrared wavelengths are preferred for biological imaging due to their ability to penetrate skin and other delicate structures safely. However, imaging with infrared light typically requires expensive detectors. This new approach allows for the use of standard, cost-effective silicon detectors for imaging, making the technology more accessible.
Additionally, the technique addresses the challenge of 'phase wrapping,' a common issue in depth measurement where deeper features become indistinguishable from shallower ones due to the limitations of light wave cycles. By utilizing two sets of entangled photons with slightly different wavelengths, the researchers effectively create a much longer synthetic wavelength, expanding the measurable range and improving depth resolution. This advancement is particularly applicable to cells and other biological materials.
The research was presented at the Conference on Lasers and Electro-Optics and was supervised by senior research associate Petr Moroshkin and Professor Jimmy Xu from Brown's School of Engineering. The project received funding from the Department of Defense and the National Science Foundation.