New technology lays groundwork for large-scale, high-resolution 3D displays
Projection approach could enable large, high-definition 3D images for digital signs and immersive experiences
Peer-Reviewed PublicationIMAGE: RESEARCHERS COMBINED TWO DIFFERENT LIGHT FIELD DISPLAY TECHNOLOGIES TO PROJECT LARGE-SCALE 3D IMAGES WITH ALMOST DIFFRACTION-LIMITED RESOLUTION. THEIR OPTICAL SETUP IS SHOWN. view more
CREDIT: BYOUNGHO LEE, SEOUL NATIONAL UNIVERSITY
WASHINGTON — Researchers have developed a prototype display that uses projection to create large-scale 3D images with ultra-high definition. The new approach helps overcome the limitations of light-field projection, which can create natural-looking 3D images that don’t require special 3D glasses for viewing.
“Our optical design could make it practical to replace 2D flat panel displays with 3D images for digital signs, entertainment, education and other applications where 3D images provide a significant enhancement,” said research team leader Byoungho Lee from Seoul National University in Korea. “Our design could also be modified to provide immersive experiences in movie theaters, for example.”
In The Optical Society (OSA) journal Optics Letters, the researchers describe how they combine two different light-field display technologies to project large-scale 3D images with almost diffraction-limited resolution. The new display is autostereoscopic, which means that it produces different 3D images so that the image can be viewed from various angles.
“We developed a way to carry out all the display processes optically without any digital processing,” said Lee. “This compensates for the limitations of each display technology to allow the creation of high-resolution 3D images on a large screen.”
CAPTION
The new display optically transforms the object display volume generated from the multifocal display into the projection volume for integral imaging by automatically mapping the rays through a microlens array (optical pickup). The transformed information can be enlarged to the large screen through a projection lens. After the projection, the object display volume is reconstructed, passing through another lens array in a similar manner to the existing integral imaging system.
CREDIT
Byoungho Lee, Seoul National University
Combining technologies
Light-field displays work by reproducing light that is reflected from an object in a way that corresponds to the actual visible position. Because autostereoscopic light field displays produce different images for different viewing angles, they require a huge amount of information to be processed. This demand creates a tradeoff between resolution and the size of the displayed image because the hardware of the display gets overwhelmed by the amount of information required.
To overcome this limitation, the researchers designed a new optical configuration that combines a multifocal display with integral imaging. Typically, a multifocal display can generate a high-quality volumetric image, but it is technically difficult to implement on a large-screen system. On the other hand, integral imaging is better at enlarging images.
In the new design, the multifocal display generates a high-resolution 3D, or volumetric, scene while the integral imaging technology enlarges it for viewing on a large screen. The information conversion between the multifocal display and integral imaging is all performed optically without any digital processing.
“Our method goes beyond merely combining two existing methods to achieving an ultrahigh-definition volumetric light-field display with almost diffraction-limited resolution,” said Lee. “We also found a way to effectively resolve the difficulty of enlarging a volumetric scene and overcame problems with information loss that tend to affect integral imaging.”
Large and high-resolution 3D images
After verifying the resolution of their prototype system, the researchers qualitatively confirmed that a volumetric image was reconstructed. The tests showed that the prototype can synthesize a volumetric image of 21.4 cm x 21.4 cm x 32 cm, which is equivalent to 28.6 megapixels and 36 times higher resolution than the original image.
“Our approach is very efficient at processing information, which enables a low computing cost as well as simple, high-quality, real-time system configuration,” said Lee. “The optical design can also be seamlessly integrated with various techniques used in existing light-field displays.”
The researchers are now working to optimize the optics and further reduce the complexity of the multifocal display to make the projector more compact. They note that because the system is a fusion of two different technologies, the performance of their proposed system will likely improve as each technology develops.
Paper: Y. Jo, K. Bang, D. Yoo, B. Lee, “Ultrahigh-definition volumetric light field projection,” Opt. Lett., 46, 17, 4212-4215 (2021).
DOI: https://doi.org/10.1364/OL.431156.
About Optics Letters
Optics Letters offers rapid dissemination of new results in all areas of optical science with short, original, peer-reviewed communications. Optics Letters accepts papers that are noteworthy to a substantial part of the optics community. Published by The Optical Society and led by Editor-in-Chief Miguel Alonso, Institut Fresnel, École Centrale de Marseille and Aix-Marseille Université, France, University of Rochester, USA. Optics Letters is available online at OSA Publishing.
About The Optical Society
The Optical Society (OSA) is dedicated to promoting the generation, application, archiving, and dissemination of knowledge in optics and photonics worldwide. Founded in 1916, it is the leading organization for scientists, engineers, business professionals, students, and others interested in the science of light. OSA’s renowned publications, meetings, online resources, and in-person activities fuel discoveries, shape real-life applications and accelerate scientific, technical, and educational achievement.
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JOURNAL
Optics Letters
ARTICLE TITLE
Ultrahigh-definition volumetric light field projection
ARTICLE PUBLICATION DATE
24-Aug-2021
Physicists make laser beams visible in
vacuum
Method developed at the University of Bonn simplifies
ultra-precise adjustment for quantum optics experiments
Peer-Reviewed PublicationIMAGE: ILLUSTRATION OF THE EXPERIMENTAL APPARATUS, WITH IN THE CENTER THE VACUUM CELL AND THE OBJECTIVE LENS EMBEDDED WITHIN. TWO OF THE FOUR LASER BEAMS ARE DRAWN (NOT TO SCALE). INSET: FLUORESCENCE IMAGE OF TWO ATOMS. view more
CREDIT: © STEFAN BRAKHANE / UNIVERSITY OF BONN
When individual atoms interact with each other, they often exhibit unusual behavior due to their quantum behavior. These effects can, for instance, be used to construct so-called quantum computers, which can solve certain problems that conventional computers struggle with. For such experiments, however, it is necessary to maneuver individual atoms into exactly the right position. "We do this using laser beams that serve as conveyor belts of light, so to speak," explains Dr. Andrea Alberti, who led the study at the Institute of Applied Physics at the University of Bonn.
Such a conveyor belt of light contains countless pockets, each of which can hold a single atom. These pockets can be moved back and forth at will, allowing an atom to be transported to a specific location in space. If you want to move the atoms in different directions, you usually need many of these conveyor belts. When more atoms are transported to the same location, they can interact with each other. In order for this process to take place under controlled conditions, all pockets of the conveyor belt must have the same shape and depth. "To ensure this homogeneity, the lasers must overlap with micrometer precision," explains Gautam Ramola, the study's lead author.
A bean in a soccer stadium
This task is less trivial than it sounds. For one thing, it requires great accuracy. "It's kind of like having to aim a laser pointer from the stands of a soccer stadium to hit a bean that's on the kickoff spot," Alberti clarifies. "But that's not all — you actually have to do it blindfolded." This is because quantum experiments take place in an almost perfect vacuum, where the laser beams are invisible.
The researchers in Bonn therefore used the atoms themselves to measure the propagation of laser beams. "To do this, we first changed the laser light in a characteristic way — we also call it elliptical polarization," Alberti explains. When the atoms are illuminated by a laser beam prepared in this way, they react changing their state in a characteristic way. These changes can be measured with a very high precision. "Each atom acts like a small sensor that records the intensity of the beam," Alberti explains. "By examining thousands of atoms at different locations, we can determine the location of the beam to within a few thousandths of a millimeter."
In this way, the researchers succeeded, for example, in adjusting four laser beams so that they intersected at exactly the desired position. "Such an adjustment would normally take several weeks, and you would still have no guarantee that the optimum had been reached," Alberti says. "With our process, we only needed about one day to do this."
CAPTION
Study leader Dr. Andrea Alberti from the Institute of Applied Physics at the University of Bonn (Germany)
CREDIT
© Volker Lannert / University of Bonn
Publication:
Gautam Ramola, Richard Winkelmann, Karthik Chandrashekara, Wolfgang Alt, Peng Xu, Dieter Meschede and Andrea Alberti: Ramsey imaging of optical traps; Physical Review Applied; http://dx.doi.org/10.1103/PhysRevApplied.16.024041
JOURNAL
Physical Review Applied
ARTICLE PUBLICATION DATE
23-Aug-2021
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