Switchable All‐Dielectric Metasurfaces for Full‐Color Reflective Display

Abstract

inherent drawbacks of transmissive displays. First, all light from a transmissive display is provided by an active light source that consumes energy continuously when the display works. Besides, the display can be quite dim under direct sunlight. Compared to transmissive display, reflective display is illuminated by ambient light. Therefore, it does not consume energy for backlight and is readable under bright sunlight. Then, we invented a "perfect" display by stacking a full-color reflective display on top of a transmissive display ( Figure S1, Supporting Information). This hybrid display can operate in either transmissive or reflective mode. It has not only low power consumption by staying at low-power reflective mode most of the time, but also superior display quality in both low-light and bright sunlight environments. While there are mature transmissive display technologies, reflective display technologies that satisfy hybrid display requirements are still unavailable. One fundamental issue is that the parallel architecture is currently adopted in full-color reflective display technologies [1] (Figure S2, Supporting Information). Even in the ideal case, the optical efficiency of a parallel architecture is limited to a poor value of 33% owing to the filling ratio of each subpixels. Additionally, none of the proposed color reflective displays could be switched into a transparent state, [2] which is critical in a hybrid display.Fortunately, the breakthroughs of nanophotonics [3] and nanofabrication technologies [4] in past decades have vigorously promoted the development of optical metasurfaces, which provide an opportunity to get a "perfect" hybrid display. With the help of precisely designed metasurfaces, incident light can be effectively manipulated. [5] Compared to metallic metasurfaces, all-dielectric metasurfaces have higher optical efficiency and broader bandwidth. [6] However, the difficulty in finding highindex and low-loss dielectrics in near-IR or visible wavelength range limited the application of all-dielectric metasurfaces to longer wavelengths. To solve this problem, we recently pioneered hybrid all-dielectric metasurfaces for efficient ultrabroadband reflector and spectrum splitting. [7] In parallel, we also tailored nanoimprint lithography (NIL) to fabricate largearea metasurfaces in near-IR or visible ranges. [8] Based on these, we proposed a novel application of all-dielectric metasurface High energy consumption and lack of readability under bright sunlight of conventional transmissive display technology greatly limit the user experience of mobile and wearable devices. To solve this issue, a hybrid display by overlaying a full-color reflective display on top of a transmissive display is invented.The key component of this technology is a full-color reflective display based on tandem switchable all-dielectric metasurfaces. The switchable all-dielectric metasurfaces in large size (average area ≈5 cm 2 ) are invented and fabricated by low-cost and high-throughput nanoimprint lithography. Each ...

Nanophotonic Structural Colors

“…248 Such systems can be used for camouflaging and active displays. 241,243,249,250 Various mechanisms are employed to tune the optical system response such as a change in scatterer size or orientation, a change in the optical properties of the local environment of optical elements, and material phase transitions as summarized in Figure 4. 212,241,247,[251][252][253][254][255][256][257][258][259][260]…”

“…An alternative strategy to geometrical tunability is to change the optical properties of the nanostructure's surrounding environment through the use of materials such as liquid crystals or electrochromic materials, as depicted in Figure 4b(i). 249,[269][270][271][272][273][274][275][276][277][278][279][280][281][282] An aluminum substrate that has nanotextures supporting surface plasmon resonances (SPRs) is covered with a layer of liquid crystal topped with a polarizer. Light passes through the polarizer and is reflected by the substrate, as shown in Figure 4b(ii).…”

Tunable Metasurfaces: The Path to Fully Active Nanophotonics

“…Subsequently, high index liquids have been proposed to achieve active switching in metasurfaces. [ 239 ] The high index liquid can be easily injected and removed to modulate the local background index of the metasurface and, therefore, the optical response in the far field. Nonlinear responses of materials are another interesting tuning mechanism based on optical pumping.…”

Dual‐Color Flexible Metasurfaces with Polarization‐Tunable Plasmons in Gold Nanorod Arrays

“…[1,2] Numerous emerging optical applications have been developed by employing metasurfaces, e.g., photonic spin Hall effect, [3] holography, [4,5] polarization control, [6] perfect absorbance, [7] data storage, [8,9] photoluminescence enhancement, [10] and biosensing. [11] In particular, metasurface-based plasmonic color have attracted tremendous attention because they promise useful applications in subwavelength full-color printing, [12][13][14] displays, [15,16] anticounterfeiting, [17,18] and optical cryptography. [19][20][21] Especially, novel display technologies show a great need for compact optical filters capable of actively changing the output color.…”