All-optical switching of structural colors excited by a Fabry–Pérot cavity inside a metal–dielectric–metal thin film stack is demonstrated. A reflectivity of >60%, a dynamic wavelength range of ≈220 nm, and a gamut coverage of >80% of standard RGB has been realized via the crystallization and re-amorphization of a low loss phase change material, that is, antimony trisulfide (Sb₂S₃).

A high-speed near-infrared (NIR) photodetector (976 nm) seamlessly incorporates multilayer indium selenide (InSe) onto a cutting-edge silicon nitride (SiN) waveguide. It exhibits exceptional optoelectronic properties, including low dark current (40 nA μm⁻¹²), high photoresponsivity (0.38 A W⁻¹), and external quantum efficiency of 48.4%. The NIR photodetector thus opens up boundless possibilities in the realms of optical interconnects, LiDAR technology, and biosensing applications.

GaSb nanowires are used as the saturable absorber elements in a waveguide laser cavity, demonstrating efficient Q-switched mode-locked lasers with a repetition rate of 8.2 GHz and a pulse duration of 31 ps operating at 1 μm wavelength. All results suggest the great potential of GaSb nanowires for the applications in next-generation ultrafast lasers.

The handedness of circular polarization of light is reversed by a modular device comprised of a dip-coated birefringent cellulose nanocrystal (CNC) film sandwiched by two CNC/polyethylene glycol composite films. Asymmetric forward and backward propagation of circular propagation resembles an optical diode at wavelengths of selective Bragg reflection.

Zero diffraction is found for symmetric dual beam incidence to a leaky symmetric waveguide grating. It enables high-contrast switching of diffraction controlled with the relative phase. It is demonstrated how the phenomenon can be used to electrically control trapping and detrapping of light.