Simulations of a Wide-Gamut and Angle-Dependent Color Reflector by Addition of a Nanometer-Thick Interference Medium in a Fabry–Perot Structure

Abstract

Traditional Fabry−Perot (F−P) structures comprising "metal/interference medium/phase-change material (PCM)" (MIP) nanostructures have achieved a color gamut close to the standard RGB (sRGB) space. However, the narrow absorption band in the visible region hinders further improvement in the gamut. Nonetheless, a large gamut is critical for display and imaging devices. This paper proposes a reflector nanostructure consisting of "metal/interference medium/phase-change materials (PCMs)/interference medium" (MIPI) to regulate the optical reflection in the visible waveband. We performed simulations to demonstrate that the addition of a 100−250-nm-thick interference medium causes the structure to change from a single to compound interference effect, thus significantly expanding the gamut (51% larger than that of the traditional MIP structure). The influences of the structure geometry and phase changes of the PCM layer on the spectral regulation were analyzed by combining experimental and simulation methods. The results indicate that the proposed structure covers almost the entire sRGB gamut. Moreover, adding the second interference medium induces a longer optical path of the incident light, which renders the structure color-sensitive to the observation angle, thus allowing for the demonstration of an anti-counterfeiting application. This nanoscale MIPI design can serve as a basis for the realization of color-regulation devices and encryption applications.

Metasurface-Controlled Holographic Microcavities

“…While previous work on metasurface optical microcavities ,, has exploited metasurfaces to control the spectral characteristics of cavity resonances and to shape the output of cavities, ,, here we for the first time experimentally realize a stable cavity mode with a complicated spatial profile inside the cavity. We image the cavity-length-dependent microscale intracavity mode experimentally and demonstrate that the concept synthesizes the designed transverse mode at a specific cavity length.…”

“…This approach can be used to enhance integrated photonic platforms. Other approaches to metasurface optical cavities exploit metasurfaces for decreasing the cavity size, steering the mode exiting the cavity, , and altering the cavity spectrum. ,, …”