Metalenses consist of an array of optical nanoantennas on a surface capable of manipulating the properties of an incoming light wavefront. Various flat optical components, such as polarizers, optical imaging encoders, tunable phase modulators and a retroreflector, have been demonstrated using a metalens design. An open issue, especially problematic for colour imaging and display applications, is the correction of chromatic aberration, an intrinsic effect originating from the specific resonance and limited working bandwidth of each nanoantenna. As a result, no metalens has demonstrated full-colour imaging in the visible wavelength. Here, we show a design and fabrication that consists of GaN-based integrated-resonant unit elements to achieve an achromatic metalens operating in the entire visible region in transmission mode. The focal length of our metalenses remains unchanged as the incident wavelength is varied from 400 to 660 nm, demonstrating complete elimination of chromatic aberration at about 49% bandwidth of the central working wavelength. The average efficiency of a metalens with a numerical aperture of 0.106 is about 40% over the whole visible spectrum. We also show some examples of full-colour imaging based on this design.

Metasurface-based components are known to be one of the promising candidates for developing flat optical systems. However, their low working efficiency highly limits the use of such flat components for feasible applications. Although the introduction of the metallic mirror has been demonstrated to successfully enhance the efficiency, it is still somehow limited for imaging and sensing applications because they are only available for devices operating in a reflection fashion. Here, we demonstrate three individual GaN-based metalenses working in a transmission window with extremely high operation efficiency at visible light (87%, 91.6%, and 50.6% for blue, green, and red light, respectively). For the proof of concept, a multiplex color router with dielectric metalens, which is capable of guiding individual primary colors into different spatial positions, is experimentally verified based on the design of out-of-plane focusing metalens. Our approach with low-cost, semiconductor fabrication compatibility and high working efficiency characteristics offers a way for establishing a complete set of flat optical components for a wide range of applications such as compact imaging sensors, optical spectroscopy, and high-resolution lithography, just named a few.

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Integration of inorganic sulfate into biological molecules plays an important role in biological systems and is directly involved in the instigation of diseases. Protein tyrosine sulfation (PTS) is a common post-translational modification that was first reported in the literature fifty years ago. However, the significance of PTS under physiological conditions and its link to diseases have just begun to be appreciated in recent years. PTS is catalyzed by tyrosylprotein sulfotransferase (TPST) through transfer of an activated sulfate from 3'-phosphoadenosine-5'-phosphosulfate to tyrosine in a variety of proteins and peptides. Currently, only a small fraction of sulfated proteins is known and the understanding of the biological sulfation mechanisms is still in progress. In this review, we give an introductory and selective brief review of PTS and then summarize the basic biochemical information including the activity and the preparation of TPST, methods for the determination of PTS, and kinetics and reaction mechanism of TPST. This information is fundamental for the further exploration of the function of PTS that induces protein-protein interactions and the subsequent biochemical and physiological reactions.

Measuring the polarization state of light and determining the optical properties of chiral materials are inherently complex issues because of the requirement of consequential measurements between different orthogonal states of polarization. Here, we introduce an on-chip polarimetry based on the visible metasurfaces for addressing the issue of polarization analysis with compact components. We demonstrate integrated metasurface chips can effectively determine a set of Stokes parameters covering a broad wave-band at visible light. For the proof of concept, the optical properties of chiral materials are measured using our proposed device, while experimental verifications are convincing by comparing with the data obtained from commercial ellipsometry.

In this study, electrochemical responses of inkjet-printed multicolored electrochromic devices (ECD) were studied to evaluate the feasibility of presenting multiple colors in one ECD. Metallo-supramolecular polymers (MEPE) solutions with two primary colors were inkjet-printed on flexible electrodes. By digitally controlling print dosages of each species, the colors of the printed EC thin film patterns can be adjusted directly without premixing or synthesizing new materials. The printed EC thin films were then laminated with a solid transparent thin film electrolyte and a transparent conductive thin film to form an ECD. After applying a dc voltage, the printed ECDs exhibited great contrast with a transmittance change (ΔT) of 40.1% and a high coloration efficiency of 445 cm(2) C(-1) within a short darkening time of 2 s. The flexible ECDs also showed the same darkening time of 2 s and still had a high ΔT of 30.1% under bending condition. This study demonstrated the feasibility to fabricate display devices with different color setups by an all-solution process and can be further extended to other types of displays.

Integrated‐resonant units (IRUs), incorporated with multiple resonators into one building block or one resonator with multiple modes, show a great capacity for achieving controllable smooth and linear phase dispersion as well as amplitude manipulation over a continuous and broad bandwidth. Based on an IRU library designed in the wavelength range of 400 to 667 nm, three achromatic deflectors showing constant steering angles of 9.5°, 19°, and 28°, respectively, are numerically validated. Achromatic metalenses with various numerical aperture (NA) values are further experimentally demonstrated, displaying an unvaried focal length throughout the bandwidth of 420–650 nm (≈50% bandwidth to the central wavelength). The focusing efficiency of the achromatic metalens with NA = 0.124 achieves 26.31%, 19.71%, and 20.37%, respectively, at wavelengths of 420, 550, and 650 nm. In addition, a multi‐nanorod IRU design is numerically optimized to achieve above 50% conversion efficiency from visible to near‐infrared (400–1400 nm). Such IRU design is then employed to construct a versatile polarization convertor, generating six different polarization states simultaneously upon one linear‐polarized illumination. The IRU approach with broadband control of amplitude and phase response provides an unprecedented platform in realizing multifunctional full‐color metadevices.

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