Researchers use laser-generated bubbles to create 3-D images in liquid

February 23, 2017, Optical Society of America
This mermaid graphic is created from laser-generated bubbles suspended in a liquid "screen" and illuminated with a halogen lamp. Credit: Kota Kumagai, Utsunomiya University

Researchers have developed a completely new type of display that creates 3D images by using a laser to form tiny bubbles inside a liquid "screen." Instead of rendering a 3D scene on a flat surface, the display itself is three-dimensional, a property known as volumetric. This allows viewers to see a 3D image in the columnar display from all angles without any 3D glasses or headsets.

In The Optical Society's journal for high impact research, Optica, researchers led by Yoshio Hayasaki of Utsunomiya University, Japan, demonstrated the ability of their volumetric bubble display to create changeable color graphics.

"Creating a full-color updatable volumetric display is challenging because many three-dimensional pixels, or voxels, with different colors have to be formed to make volumetric graphics," said Kota Kumagai, first author of the paper. "In our display, the microbubble voxels are three-dimensionally generated in a liquid using focused femtosecond laser pulses. The bubble graphics can be colored by changing the color of the illumination light."

Although the new work is a proof of concept, the technology might one day allow full-color updatable volumetric displays. These types of displays could be used for art or museum exhibits, where viewers can walk all the way around the display. They are also being explored for helping doctors visualize a patient's anatomy prior to surgery or to let the military study terrain and buildings prior to a mission.

"The volumetric bubble display is most suited for public facilities such as a museum or an aquarium because, currently, the system setup is big and expensive," said Kumagai. "However, in the future, we hope to improve the size and cost of the laser source and optical devices to create a smaller system that might be affordable for personal use."

Using lasers to make bubbles

The bubbles for the new display are created by a phenomenon known as multiphoton absorption, which occurs when multiple photons from a femtosecond laser are absorbed at the point where the light is focused. Multiphoton absorption allowed the researchers to create microbubbles at very precise locations by moving the focus of the laser light to various parts of a liquid-filled cuvette that acted as a "screen." Using a high-viscosity, or thick, liquid prevents the bubbles, once formed, from immediately rising to the top of the liquid.

The bubble graphics are viewable when they scatter light from an external light source such as a halogen lamp or high-power LED. The researchers produced monochromatic images in white, red, blue and green by switching the color of the illuminating LED. They say that illuminating the graphics with a projector could create different colors in different regions of the image.

Rather than creating each bubble one by one, the researchers used a computer-generated hologram to form 3D patterns of laser light that let them control the number and shapes of the microbubble voxels. This approach also increased the amount of light scattered from the microbubbles, making the images brighter.

In the paper, the researchers demonstrate their technique by creating a sequence of 2D bubble images of a mermaid, a 3D rendered bunny, and 2D dolphin graphics in four different colors. They also showed that microbubble formation depends on the irradiation energy of the laser and that the contrast could be modified by changing the number of laser pulses used to irradiate the liquid.

"Our bubble graphics have a wide viewing angle and can be refreshed and colored," said Kumagai. "Although our first volumetric graphics are on the scale of millimeters, we achieved the first step toward an updatable full-color volumetric ."

The researchers are now developing a system that would use a stream inside the liquid to burst the bubbles, allowing the image to be changed or cleared. They are also working on methods that could allow the formation of larger graphics, which requires overcoming spherical aberrations caused by the refractive index mismatch between the liquid screen, the glass holding the liquid, and air.

Explore further: Images in the air: Researchers turn to femtosecond lasers

More information: Kota Kumagai et al, Volumetric bubble display, Optica (2017). DOI: 10.1364/optica.4.000298

Related Stories

Images in the air: Researchers turn to femtosecond lasers

June 30, 2015

Say the word "display" and one easily anticipates an image on a screen or on a table surface or within a next-gen box enclosure. Last year, Aerial Burton went another route reminding everyone that something else is possible. ...

Aluminum nanoparticles could improve electronic displays

January 6, 2016

Whether showing off family photos on smartphones or watching TV shows on laptops, many people look at liquid crystal displays (LCDs) every day. LCDs are continually being improved, but almost all currently use color technology ...

Creating high-resolution full-color moving holograms in 3-D

February 4, 2015

Three-dimensional (3D) movies, which require viewers to wear stereoscopic glasses, have become very popular in recent years. However, the 3D effect produced by the glasses cannot provide perfect depth cues. Furthermore, it ...

Bubbles are the new lenses for nanoscale light beams

August 9, 2013

Bending light beams to your whim sounds like a job for a wizard or an a complex array of bulky mirrors, lenses and prisms, but a few tiny liquid bubbles may be all that is necessary to open the doors for next-generation, ...

Recommended for you

Physicists reveal why matter dominates universe

March 21, 2019

Physicists in the College of Arts and Sciences at Syracuse University have confirmed that matter and antimatter decay differently for elementary particles containing charmed quarks.

ATLAS experiment observes light scattering off light

March 20, 2019

Light-by-light scattering is a very rare phenomenon in which two photons interact, producing another pair of photons. This process was among the earliest predictions of quantum electrodynamics (QED), the quantum theory of ...

How heavy elements come about in the universe

March 19, 2019

Heavy elements are produced during stellar explosion or on the surfaces of neutron stars through the capture of hydrogen nuclei (protons). This occurs at extremely high temperatures, but at relatively low energies. An international ...

Trembling aspen leaves could save future Mars rovers

March 18, 2019

Researchers at the University of Warwick have been inspired by the unique movement of trembling aspen leaves, to devise an energy harvesting mechanism that could power weather sensors in hostile environments and could even ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.