Infrared tubular microcavity based on rolled-up GeSn/Ge nanomembranes

High-Q resonance in GeSn-based bound states in the continuum microcavity

In recent years, the investigations of lasers based on group IV material have been limited by the low quality (Q) factor of the resonant modes. With the improvement of the optical bound states in the continuum (BICs) in various dielectric systems, we propose a novel design that takes advantages of both the direct bandgap dielectric material GeSn and the BIC phenomenon. In addition to the demonstration of the unprecedented high-Q factors (i.e., ∼10¹⁰) that improve the emission process, the vertical symmetry broken structure can emit light at the wavelength of 1870 nm with higher luminous intensity (i.e., ∼24). The modulation effect of the material and geometric parameters on the Q value and the luminous intensity of the structure are also demonstrated. Our investigations provide useful guidelines for potential applications such as on-chip light sources in group IV photonics and optical communications.

Microdroplet-guided intercalation and deterministic delamination towards intelligent rolling origami

Three-dimensional microstructures fabricated by origami, including folding, rolling and buckling, gain great interests in mechanics, optics and electronics. We propose a general strategy on on-demand and spontaneous rolling origami for artificial microstructures aiming at massive and intelligent production. Deposited nanomembranes are rolled-up in great amount triggered by the intercalation of tiny droplet, taking advantage of a creative design of van der Waals interaction with substrate. The rolling of nanomembranes delaminated by liquid permits a wide choice in materials as well as precise manipulation in rolling direction by controlling the motion of microdroplet, resulting in intelligent construction of rolling microstructures with designable geometries. Moreover, this liquid-triggered delamination phenomenon and constructed microstructures are demonstrated in the applications among vapor sensing, microresonators, micromotors, and microactuators. This investigation offers a simple, massive, low-cost, versatile and designable construction of rolling microstructures for fundamental research and practical applications.

Rolling microstructures have great potential among optics and micromechanics but on-demand construction with versatile materials remains challenging. Here Xu et al. precisely construct 3D rolling microstructures by liquid-triggered delamination in predictable manner and demonstrate their applications.