The Future of Technology: Ghost Imaging
A team of Australian physicists has broken new ground on a technique called ‘ghost imaging,’ used to create an image of an object using atoms that do not actually interact with it. This is a revolutionary technique that can lead to better quality control of nanoscale manufacturing, including atomic-scale 3D printing.
The latest application of quantum mechanics has led to the deeper exploration of ghost imaging. This is a technique that allows the image of an object to be created despite the use of atoms which never interact with the object itself. The technique was first demonstrated in 1995, using light instead of atoms to produce images, and has led to plenty of research into its potential uses.
First of Its Kind?
According to a paper published by physicists Jeffery Shapiro and Baris Erkmen, ghost imaging produces the image of an object by ‘correlating the intensity of two light beams, neither of which independently carries information about the shape of the object.’
The latest findings have described the use of helium-4 to create a ghost image, the first of its kind to be created with mass. Helium-4 is a boson, also known as a photon, which can produce a bright image on a dark background. Physicist Hongchao Liu at the University of Birmingham, UK, has been exploring the difference between ghost imaging with bosons (i.e. photons) and ghost imaging using fermions (electrons and protons).
Australian researchers have used bosons to create a ghost image. No one has been able to create a ghost image with fermions till date, but if this were to happen, the resulting ghost image would appear as a dark image on a light background.
What Is the Process behind Ghost Imaging?
Ghost imaging forms an image of an object using data from two light beams of varying intensities. One beam is the ‘object beam’ that touches the object, and the other is a ‘reference beam’ which does not touch the object. Although previously, this process has only been conducted using visible and infrared light, now it has also been done using X-rays. This method can eventually help to reduce the damage caused by radiation exposure during X-ray imaging.
Ghost imaging has allowed physicists to obtain highly-resolved images of objects even in the presence of noise or turbulence. This has enabled the production of temporal resolution at the picosecond level. These images are not affected by temporal distortion, which can occur in the object’s surroundings. Every digital image is subjected to a series of stages during its acquisition, storage, and transmission, and can suffer from temporal distortion in the process.
Ghost imaging is essentially the process of combining two photo-detectors. The first is a high-spatial-resolution detector, which measures a field that hasn’t interacted with the object in question. The second one is a bucket detector that displays the field that has interacted with the object. Both photo-detectors combine to create a clearer image of the object than was possible earlier.
Ghost Imaging Using Atoms
In 2016, physicists at ANU Research School of Physics and Engineering (RSPE) have created a technique of ghost imaging using atoms instead of light. According to Associate Professor Andrew Truscott, the experiment used correlated pairs of atoms, placed at a distance of six centimetres from each other. These atoms were then used to generate an image of the ‘ANU’ logo. Next, one atom from every pair was directed towards a mask, which spelt out ANU in cut-out form.
Professor Truscott added, “Only atoms that pass through the mask reach a ‘bucket’ detector placed behind the mask.” This mask recorded a ping every time an atom hit it, and the second atom from every pair recorded a ‘ping’ as well as the atom’s location on the spatial detector.
Using this method, the physicists were able to match the timing of the pings from the pairs of atoms, thereby discarding any atom whose partner had not passed through the mask.
This process allowed the image of the letters ‘ANU’ to be recreated, despite the fact that the atoms which formed the image on the spatial detector had never touched the mask. ‘Ghost’ imaging seems to be an apt title for this technique.
What Are the Uses of Ghost Imaging?
Previously, ghost imaging had been made possible using light, and this led to the development of remote-sensing equipment for use in turbulent environments. Ghost imaging uses atoms and can potentially be used for encryption and military intelligence.
Professor Ken Baldwin, ex-member of the experimenting team at RSPE, said that ghost imaging can be used to create a new method of controlling the quality of nanoscale manufacturing; for example, atomic scale 3-D printing, or manufacturing a microchip or a Nano-device. Companies such as digsemi and Ismolex, which manufacture electronic components can benefit in terms of improved production quality in the future, thanks to this latest discovery.
Professor Sean Hodgman, also a member of the research team, added that this new technique can mark the start of many changes. It can help investigate the entanglement between extremely large particles, thereby helping with the development of quantum computation. He said this research could help explore the area of quantum entanglement, also known as Einstein’s spooky action at a distance.
Only time will tell what other benefits the breakthrough in ghost imaging will bring. For now, researchers are trying to understand the potential practical benefits that this discovery can bring with it in other fields.
Rachel Oliver is a freelancer who has a way with words. She likes to write about anything and everything under the sun, but themes like technology, electrnoics & gadgets, sports, construction and maintenance interests her more. You can get in touch with her on Google+, Facebook, and Twitter.