We’ve seen the 3D phone fad come and go, with devices like the Evo 3D, that used a parallax barrier to achieve autostereoscopy (that is, 3D viewing without glasses). These displays aren’t holograms, they are just showing your eyes two different images like a 3D movie or a stereopticon. However, researchers from Australia and China are hoping to change that. They’ve developed a nano-hologram (their term) that is about 1000 times thinner than a human hair. You can see a video about the invention, below.
Conventional holograms modulate the phase of light to give the illusion of three-dimensional depth. But to generate the required phase shifts, those holograms need to be as thick as the optical wavelengths involved. The researchers claim the holograms are “simple” to make, but that depends on what you compare it to. You need some exotic materials, vacuum deposition gear, and a laser that can do femtosecond-long pulses.
The research team has broken this thickness limit with a 25 nanometer hologram. Their technique relies on a topological insulator material a novel quantum material that holds a low refractive index in the surface layer but a much higher refractive index in the bulk of the material. This forms an intrinsic optical resonant cavity which can enhance the phase shifts and makes holography possible.
The next step is to develop a rigid thin film to overlay an LCD screen. The current version has pixels at least ten times too large to be practical for that application, so that’s another hurdle to overcome.
We’ve seen screens that shoot 3D images on movies like Star Wars for years. This isn’t it yet, but it is the next step. Imagine a phone, a wrist watch, or a contact lens that could generate a holographic image. Or a garbage-can-sized robot.
If your resources don’t stretch to the creation of real holograms, you can always create something that almost looks like one.