Researchers Develop Flat Magic Window With Liquid Crystals
For the very first time, scientists empolyed liquid crystals to assemble a flat magic window — a clear machine that makes a concealed picture when gentle shines on it. The technological know-how represents a novel twist on a really outdated light-weight trick.
Thousands of several years ago, artisans in China and Japan manufactured bronze mirrors that seemed like typical flat mirrors whilst viewing one’s reflection but produced a different impression when illuminated by immediate daylight. It took scientists till the early 20th century to determine out that these equipment work due to the fact an image forged into the back again of the mirror generates little surface variations that bring about the image to kind – and it took engineers right up until now to implement the similar principle to liquid crystals for superior-tech displays.
“The magic window we developed seems completely flat to the bare eye but, in point, has slight variations that make an impression in reaction to light,” stated research crew leader Felix Hufnagel from the University of Ottawa. “By developing the window to be fairly clean, the image that is produced can be viewed more than a significant range of distances from the window.”
In Optica, Optica Publishing Group’s journal for higher-affect research, Hufnagel and colleagues explain the approach they formulated for building transparent liquid crystal magic windows that can produce any desired graphic. The system can also be used to make magic mirrors that reflect, relatively than transmit, gentle to produce an picture.
“Using liquid crystals to make magic home windows or mirrors could 1 working day make it feasible to develop a reconfigurable model for generating dynamic artistic magic home windows or films,” claimed Hufnagel. “The skill to receive a very long depth of aim could also make the solution valuable for 3D displays that generate steady 3D photographs even when viewed from various distances.”
Creating magic with liquid crystals
Despite the fact that scientists have understood for decades that the historic bronze magic mirrors formed visuals as a outcome of modest surface variations, it was not right until 2005 that Michael Berry, a mathematical physicist at the
Stable images over multiple distances
“On a conceptual level, the theory developed by Berry was instrumental in determining how these liquid crystals must be oriented to create an image that is stable over a large distance,” said Hufnagel. “Our use of flat optical elements and a liquid crystal pattern with gentle variations prescribed by Berry’s Laplacian image theory allows the magic windows to appear normal, or flat, when one looks through them.”
After fabricating a magic mirror and window, the researchers used a camera to measure the light intensity patterns produced by both devices. When illuminated with a laser beam, both the mirror and window produced a visible image that remained stable even as the distance between the camera and the mirror or window changed. The researchers also showed that the devices created images when illuminated with an LED light source, which would be more practical to use in real-life applications.
The researchers are now working to use their fabrication approach to create quantum magic plates. For example, two of these plates could create entangled images which one could use to study new quantum imaging protocols. They are also exploring the possibility of fabricating magic windows using approaches other than liquid crystals. For instance, using dielectric metasurfaces to make a magic window device could reduce its footprint while increasing bandwidth.
Reference: “Flat Magic Window” by Felix Hufnagel, Alessio D’Errico, Hugo Larocque, Fatimah Alsaiari, Jeremy Upham and Ebrahim Karimi, 5 May 2022, Optica.