On the Cover: Microcavity exciton polaritons at room temperature

This paper aims to review recent theoretical and experimental developments of exciton polaritons operating at room temperature, and includes a comprehensive theoretical background, descriptions of intriguing phenomena observed in various physical systems, as well as accounts of optoelectronic applications.

On the Cover: Centimeter scale color printing with grayscale lithography

The image illustrates the design concept of the pixelated Fabry-Perot (F-P) cavities. Structural color comes from the light interactions with sub-wavelength structures. Compared with conventional painting technology using chemical dyes, structural color has a broader range of technological applications. Among various color management technologies, F-P cavity represents an important solution for generating vivid colors. However, the fabrication of pixelated F-P cavities has mainly relied on the slow electron beam lithography process.

On the Cover: Spatially engineered nonlinearity in resonant metasurfaces

Periodic poling of resonant lithium niobate metasurfaces modifies their nonlinearity and enables tailoring the diffraction pattern of second harmonic generated by the metasurface. It adds another degree of freedom for designing nonlinear metasurfaces.

On the Cover: Metasurfaces enabled dual-wavelength decoupling of near-field and far-field encoding

The small size and rich functions of metasurfaces have great potential for the development of new optical devices. The research group theoretically proved that the metasurface can realize the complete decoupling of the near-field and far-field functions of the same polarization at two working wavelengths. While the near-field encodes intensity patterns, the far-field functions can be holographic, focusing, and beam deflecting. The cover image shows that when a metasurface is illuminated by the light at 1064 nm and 1550 nm, the near-field intensity distribution displays the numbers 1064 and 1550, and the holographic pattern shows the emblem of Nanjing University and its landmark building North Building.