For holographic display systems, the resolution and field of view are ultimately limited by the size of the pixels from which incident light is scattered, interfering to produce the projected image. Modern nanofabrication and lithographic processes make it possible to form precisely-defined subwavelength nanostructures, which, as reported by Prof. Haider Butt and co-workers for arrays of carbon nanotubes (CNTs), can be used to scatter light in a controlled way, resulting in extremely high-resolution, low-noise holographic images.
Due to their metallic properties, CNTs exhibit strong diffraction effects when arranged on dimensions close to the wavelength of visible light. The researchers first calculated using Fourier optics the precise array required to produce a diffraction pattern spelling “CAMBRIDGE” and subsequently fabricated this on a silicon substrate using plasma-enhanced chemical vapour deposition. When the surface was irradiated with laser light, the desired diffraction pattern in the far field was successfully obtained (schematic of experimental setup (a) and the captured diffraction pattern on a semitransparent screen (b) are shown below).
The CNTs comprising the array represent the smallest pixels ever used to produce holograms. The nanometer-scale dimensions provide not only high resolution, but also high contrast and a large field of view. With the fine control of scattering demonstrated, this work brings the use of complex nanostructures in 3D holography a significant step closer.
The research was reported in Advanced Optical Materials, a new section in Advanced Materials dedicated to breakthrough discoveries and fundamental research in photonics, plasmonics, metamaterials, and more, covering all aspects of light-matter interactions. To get Advanced Optical Materials email alerts click here. Advanced Optical Materials will start as an independent journal in 2013. More information can be found on www.advopticalmat.de.