PORTLAND, Ore. Quantum-entangled images--two randomly fluctuating pictures separated in space but inextricably linked through their complementary features--have been captured in real-time for the first time.
The advance was achieved at the Joint Quantum Institute (JQI, College Park, Md.) by a joint research team from the National Institute of Standards and Technology and the University of Maryland. The new method, which is said to be simple to implement compared to earlier attempts, reveals new details in hard-to-see objects. The researchers also generated reams of entangled data that prove useful in future quantum computers, according to JQI researchers Paul Lett and Vincent Boyer.
The technique works using linked laser beams originating from a single point. The result was twin images--one inverted and the other backwards--at separate locations. Random fluctuations in the laser beam originating with the first image were mirrored in the second image. Very subtle differences revealed new details. By matching the two images and subtracting their differences, much greater detail was possible compared to using other photographic techniques, the researchers claimed.
|Twin laser beams transmit images of a cat-like face at two slightly different frequencies
(shown with false colors of orange and purple) revealing details in the twisted lines indicating random fluctuations entangled in the two images.|
Earlier laboratory setups proved difficult to implement since they required light to bounce back and forth between precisely spaced mirrors. The new method uses four-wave mixing, whereby a probe laser passes through a mask containing the visual pattern to be imaged. It then joins a higher-power pump beam inside a cell of rubidium gas. The gas atoms absorb and re-emit an amplified image and its complement (inverted and upside down) with the same energy and momentum as the original, but at a slightly different color.
The subsequent image pairs contain more information than conventional images, which only record the reflections off the surface of an object, or 3D holograms, which record the phase of the passing light.
In addition, quantum videos record the quantum fluctuations in a light source, including the slight brightening and dimming of the imaging laser. These quantum uncertainties reveal features in their moment-to-moment fluctuations, which can be used to remove noise from the images. The technique enables clearer viewing of hard-to-see objects while opening the door to higher-density data storage methods.
Next, the researchers plan to combine their imaging technique with slowed-down laser beams that could be used to process, store and communicate information with more accuracy and capacity than is possible with non-quantum mechanical techniques.