Metasurface-based nanoprinting (meta-nanoprinting) has fully demonstrated its advantages in ultrahigh-density grayscale/color image recording and display. A typical meta-nanoprinting device usually has image resolutions reaching 80 k dots per inch (dpi), far exceeding conventional technology such as gravure printing (typ. 5 k dpi). Besides, by fully exploiting the design degrees of freedom of nanostructured metasurfaces, meta-nanoprinting has been developed from previous single-channel to multiple-channels, to current multifunctional integration or even dynamic display. In this review, we overview the development of meta-nanoprinting, including the physics of nanoprinting to manipulate optical amplitude and spectrum, single-functional meta-nanoprinting, multichannel meta-nanoprinting, dynamic meta-nanoprinting and multifunctional metasurface integrating nanoprinting with holography or metalens, etc. Applications of meta-nanoprinting such as image display, vortex beam generation, information decoding and hiding, information encryption, high-density optical storage and optical anti-counterfeiting have also been discussed. Finally, we conclude the opportunities and challenges/perspectives in this rapidly developing research field of meta-nanoprinting.

Due to its unique intensity distribution, self-acceleration, and beam self-healing properties, Airy beam holds great potential for optical wireless communications in challenging channels, such as underwater environments. As a vital part of 6G wireless network, the Internet of Underwater Things requires high-stability, low-latency, and high-capacity underwater wireless optical communication (UWOC). Currently, the primary challenge of UWOC lies in the prevalent time-varying and complex channel characteristics. Conventional blue Gaussian beam-based systems face difficulties in underwater randomly perturbed links. In this work, we report a full-color circular auto-focusing Airy beams metasurface transmitter for reliable, large-capacity and long-distance UWOC links. The metasurface is designed to exhibits high polarization conversion efficiency over a wide band (440-640 nm), enabling an increased data transmission rate of 91% and reliable 4 K video transmission in wavelength division multiplexing (WDM) based UWOC data link. The successful application of this metasurface in challenging UWOC links establishes a foundation for underwater interconnection scenarios in 6G communication.

Artificial-intelligence-generated content has driven explosive data traffic growth in data-center interconnects. Traditional direct detection solutions struggle with limited spectral efficiency and distance, prompting the shift to coherent optics for cost-sensitive short-reach links. One specific challenge is integrating low-cost lasers while overcoming severe phase noise on high-order modulation formats. Here, we propose a residual carrier modulation scheme for precise and efficient carrier frequency and phase recovery. The residual optical carrier can continuously track phase fluctuations without redundancy compared with discrete time-domain pilots, and address the digital-to-analog convertor resolution reduction issue of frequency-domain digital pilots. In proof-of-concept experiments, we transmit a net 1-Tb/s probabilistic-shaped 256-ary quadrature amplitude modulated (PS-256-QAM) signal using a 3 MHz distributed feedback (DFB) laser. Our scheme improves bitrate by 41% compared to conventional time-domain pilots, achieving a record laser linewidth sum and symbol duration product of 6.89 × 10⁻⁵. This approach supports MHz linewidth DFB lasers in low-cost coherent optical communications.