A 3-D image can be literally that with volumetric bubble technology from Utsunomiya University, Japan. A proof of concept study demonstrated the generation of 3-D images in liquid by focused femtosecond laser pulses.

Instead of a 3-D scene on a flat surface, viewers see a 3-D image in the columnar display from all angles without any 3-D glasses or headsets.

Image sequence of 2D graphics image known as “Mermaid” rendered by femtosecond laser-induced microbubbles.Image sequence of 2D graphics image known as “Mermaid” rendered by femtosecond laser-induced microbubbles.Full-color updatable volumetric displays could be used for art or museum exhibits, where viewers can walk around the display. Other potential applications include use by physicians to visualize a patient’s anatomy prior to surgery, or as a military tool to study terrain and buildings prior to a mission.

The bubbles for the new display are created by 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 (see video).

The bubble graphics are viewable when they scatter light from an external light source such as a halogen lamp or high-power LED. Monochromatic images in white, red, blue and green were produced by switching the color of the illuminating LED.

A computer-generated hologram was used to form 3-D patterns of laser light, enabling the researchers to control the number and shapes of the microbubble voxels, or 3-D pixels. This approach also increased the amount of light scattered from the microbubbles, making the images brighter. A sequence of 2-D bubble images of a mermaid, a 3-D rendered bunny, and 2-D dolphin graphics in four different colors were created to showcase the technique.

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