The invention of technology has of late seen the introduction of three dimensional holographic images and floating displays outside a screen. These have long been a preferred entity of science fiction movies such as the rescue message carried by R2-D2 in Star Wars.
The accomplishment of James Cameron’s 3D movie Avatar caused a great worldwide interest in flexible, high-definition and floating display devices.
The bottom line is that the desire of optically displaying a 3D object has been regularly driving the revolution of display technologies over the past decade.
3D imagery is currently seen with the aid of special glasses.
Worth noting is that the revenue generated by this 3D technology market in 2013 exceeded US$93.21 billion (almost double the global solar market), and is expected to grow up to US$279.27 billion by 2018.
A 3D image with no glasses
The idea of optical holography provides innovative means for recording and displaying both 3D amplitude and phase of an optical wave that comes from an object of interest.
The physical understanding of high definition and wide viewing angle holographic 3D displays relies on the generation of a digital holographic screen which is composed of many small pixels.
These pixels are used to curve light which is delivering the information for display. The angle of curving is measured by the refractive index of the screen material – according to the holographic correlation.
If the refractive index pixels get smaller, the bending angle will get larger once the beam passes through the hologram. This nanometer size of pixels is of paramount significance for the reconstructed 3D object to be clearly viewed in a wide angle.
The process is compound but the key main physical step is to control the heating of photoreduction of graphene oxides, derivatives of graphene with analogous physical structures but existence of additional oxygen groups.
Through a photoreduction procedure, devoid of involving any temperature increase, graphene oxides can be condensed toward graphene by absorbing a single femtosecond pulsed laser beam.
Changes in the refractive index can be created during the photoreduction.
This technique allows the reconstructed floating 3D object to be clearly and naturally viewed in a wide angle of up to 52 degrees.
This result corresponds to an improvement in viewing angles by one-order-of-magnitude compared with the current available 3D holographic displays based on liquid crystal phase modulators, limited to a few degrees.
Apart from that, the regular refractive index change over the visible spectra in reduced graphene oxides enables full-colour 3D display.
The demonstrated graphene 3D display currently allows images of up to 1cm. But there is no restraint for the up scalability of this technique.
Due to exceptional mechanical strength of graphene based materials, this technique can assist to transfer graphene-enabled wearable displaying devices from 2D into floating 3D displays.
In future, the graphene 3D display at tens of centimetre scale, perfect for the wearable displaying devices, will be available within five years.
This new generation floating 3D display technology has potential applications on many aspects such as military devices, entertainment, remote education and medical diagnosis.