Chunying Guan

We demonstrate a Vernier effect-enhanced all-fiber gas pressure sensor with an extremely simple structure. The sensor consists of a rectangular air cavity near the end face of a single-mode fiber (SMF) fabricated by femtosecond laser micromachining. The two walls of the air cavity and the end face of the SMF form micro cascaded Fabry–Perot interferometers to generate the Vernier effect.

The physics of resonant metasurfaces underpins many electromagnetic functionalities with enhanced performance by virtue of resonant excitations. Resonances originating from bound states in the continuum (BICs) were recently recognized in photonics for their superior optical properties, strong local field enhancement, and suppression of radiative losses.

We introduce the concept of polarized vortex Smith–Purcell radiation by the interaction of an electron beam and cascaded metasurfaces. The spin and orbital angular momenta of Smith–Purcell radiation are determined by the cascaded metasurface that consists of a grating and a phase gradient metasurface. The grating converts the electron beam radiation into the desired polarized light, while the phase gradient metasurface generates the vortex light.