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Spatial Light Modulators

Manipulation of light at the nanoscale is cornerstone for the realization of miniaturized optical devices with enhanced efficiencies. In this regard, the emerging technology of flat optics allows controlling the wavefront of light with unprecedented resolution. It uses arrays of sub-wavelength nanostructures, so called nanoantennas, to realize ultra-thin components that can replace, or even outperform, traditional bulk optics, including prisms, lenses, etc. (see Figure 1a). Besides the obvious advantage in terms of size, of great importance in wearables and hand-held consumer electronics, this technology is called to revolutionize optical technologies in the near future by reducing production costs and allowing integrated optoelectronic devices using CMOS compatible fabrication techniques, thus shifting the manufacturing paradigm of optical components.
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Figure 1. (a) Example of flat optics lens outperforming traditional bulk optics. This lens has a numerical aperture in free space of 0.99, exceeding any commercially available (Nano Letters 2018). (b) Metasurface-enabled hologram in a near-eye display, augmented reality configuration. The 3D image generated contains full depth cues and is free from the vergence-accommodation issue of traditional stereoscopic 3D displays.

Besides, this novel technology allows hologram generation with ultra-high pixel densities and unparalleled viewing angles. This holds promise in the realization of a whole new class of display technologies offering a more immersive experience for the user, producing true three-dimensional holographic images with full depth-perception that can be seen by naked eye (see Figure 1b). In order to realize such devices, our group develops new approaches to dynamically control the individual response of these nanoantennas (see Figure 2), as to create a novel class of Spatial Light Modulators that allows real time control of the wavefront of light with as high as 60,000ppi pixel densities.

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Figure 2. (a) Concept art showing the small-footprint nanoantenna-based spatial light modulator (NSLM). (b) Photograph, PCB board and SEM images of the first actual prototype of 1D, linear NSLM (Science 2019).

To do so, our group works holistically with collaborators from different disciplines, ranging from integrated circuit design and advanced chip packaging to material science and system integration, towards the ultimate goal of creating the next generation of optical technologies for dynamic wavefront manipulation (see Figure 3). We believe that these technologies will have an impact in diverse areas, ranging from near-eye displays, such as VR and AR, and heads-up displays to 3D ranging and sensing, adaptive optics, optical communications or quantum optics, to mention some.