Miniaturized solar-blind ultraviolet imaging system enabled by a diffractive/refractive hybrid.

In this paper, we demonstrated a miniaturized diffractive/refractive hybrid system based on a diffractive optical element and three refractive lenses to achieve solar-blind ultraviolet imaging within a range of 240-280 nm. We experimentally demonstrate the optical system has both outstanding resolution and excellent imaging capability. The experiments demonstrate that the system could distinguish the smallest line pair with a width of 16.

High Performance Graphene-C -Bismuth Telluride-C -Graphene Nanometer Thin Film Phototransistor with Adjustable Positive and Negative Responses.

Graphene is a promising candidate for the next-generation infrared array image sensors at room temperature due to its high mobility, tunable energy band, wide band absorption, and compatibility with complementary metal oxide semiconductor process. However, it is difficult to simultaneously obtain ultrafast response time and ultrahigh responsivity, which limits the further improvement of graphene photoconductive devices. Here, a novel graphene/C /bismuth telluride/C /graphene vertical heterojunction phototransistor is proposed.

Meta-Optics-Empowered Switchable Integrated Mode Converter Based on the Adjoint Method.

Monolithic integrated mode converters with high integration are essential to photonic integrated circuits (PICs), and they are widely used in next-generation optical communications and complex quantum systems. It is expected that PICs will become more miniaturized, multifunctional, and intelligent with the development of micro/nano-technology. The increase in design space makes it difficult to realize high-performance device design based on traditional parameter sweeping or heuristic design, especially in the optimal design of reconfigurable PIC devices.

Minimized two- and four-step varifocal lens based on silicon photonic integrated nanoapertures.

Integration of optical waveguide and subwavelength structure may help address the problems of large footprint, low robustness, and small operation bandwidth, those of that are typically inborn in traditional integrated optical devices. Here, a design method of an ultra-compact small footprint lens is proposed. Combing particle swarm optimization (PSO) algorithm with spatial multiplexing technology, we successfully integrated two- and four-step varifocal lenses on SOIs chips with small footprint of 35×35 µm, non-mechanically leading to 2.

Tunable beam manipulation based on phase-change metasurfaces.

A metasurface combined with phase-change material (GST) is proposed to act as a switchable wave plate to adjust spin-orbit interactions (SOIs), so that the polarization and phase of the reflected light are simultaneously manipulated. A converter, which could act as a quarter-wave plate or three-quarter-wave plate when the GST layer is in the amorphous or crystalline state, and a switch, which could act as a mirror (corresponding to the "OFF" state of SOIs) or half-wave plate (corresponding to the "ON" state of SOIs) when the GST layer is in the amorphous or crystalline state, are designed, respectively. Consequently, a convertible vectorial beams converter, which could generate radial or azimuthal polarization, is designed when the GST layer is in the amorphous or crystalline state.