In the memorable 1977 Star Wars movie scene, Luke Skywalker sees the droid R2D2 project a 3D image of a woman draped in a white robe.
“Help me, Obi-Wan Kenobi. You’re my only hope,” pleads Princess Leia before the projection is stopped.
In an exciting breakthrough known informally at Brigham Young University as “the Princess Leia Project”, BYU researchers have succeeded in creating a 3D image that takes up real space and can be viewed from almost any angle. The January 24, 2018 news story released in the BYU newsletter describes the process as being similar to creating a 3D-printed object but using a single particle and a laser beam to illuminate it. Daniel Smalley, a BYU electrical and computer engineering professor and holography expert, was able to move a single plant collagen particle through the air and manipulate it’s path into a pattern that, when lit up by a laser beam hitting it, appeared to be a single, static image. The researchers created a small image of planet Earth that appeared to hover over a fingertip.
Think of moving a 4th-of-July sparkler quickly through the air in the dark – a repetitive circular movement seems to “paint” a solid circle image in the darkness. By moving a particle through the air in the lab and then lighting it with a laser beam, the result is what appears to be a static image.
“In simple terms, we’re using a laser beam to trap a particle, and then we can steer the laser beam around to move the particle and create the image,” said undergrad coauthor Erich Nygaard.
Definitely NOT a Hologram
Smalley emphasizes that the images they are creating are not holograms. A hologram creates a 3D image by passing light through a 2D screen that manipulates the light’s path. The hologram technique can create stunning, full-color 3D images, but the light must always emerge from a 2D surface and thus can only be viewed from certain angles.
Smalley’s 3D image is called a ‘volumetric image’ because the image is being physically created in 3D space.
“The image of Princess Leia is not what people think it is: It’s not a hologram,” Smalley explains in the BYU article. “A 3D image that floats in air, that you can walk all around and see from every angle, is actually called a volumetric image. Examples of volumetric images include the 3D displays Tony Stark interacts with in “Iron Man” or the massive image-projecting table in “Avatar.””
Next Steps for a Usable Volumetric Display
Although Smalley’s volumetric images are able to display an image in high resolution – currently up to 1600dpi – the images created so far are only millimeters across. Complex moving images and larger visualizations are the next step in Smalley’s research. To achieve a display that is larger and can be used for real-world applications, his team will need to find ways to speed up the movement of the particles and to control several of them at once.
Nature magazine has a great article about the breakthrough, including a three-minute video about the process:
For more information:
Article in Nature magazine
Article in BYU News
photo credits: Daniel Smalley Lab, Nate Edwards/BYU Photo