Two-dimensional (2D) materials have drawn tremendous attention in recent years. Being atomically thin, stacked with van der Waals force and free of surface chemical dangling bonds, 2D materials exhibit several distinct physical properties. To date, 2D materials include graphene, transition metal dichalcogenides (TMDS), black phosphorus, black P As , boron nitride (BN) and so forth. Owing to their various bandgaps, 2D materials have been utilized for photonics and optoelectronics. Photodetectors based on 2D materials with different structures and detection mechanisms have been established and present excellent performance. In this Review, localized field enhanced 2D material photodetectors (2DPDs) are introduced with sensitivity over the spectrum from ultraviolet, visible to infrared in the sight of the influence of device structure on photodetector performance instead of directly illustrating the detection mechanisms. Six types of localized fields are summarized. They are: ferroelectric field, photogating electric field, floating gate induced electrostatic field, interlayer built-in field, localized optical field, and photo-induced temperature gradient field, respectively. These localized fields are proved to effectively promote the detection ability of 2DPDs by suppressing background noise, enhancing optical absorption, improving electron-hole separation efficiency, amplifying photoelectric gain and/or extending the detection range.

Lunar Penetrating Radar (LPR) is one of the important scientific instruments onboard the Chang'e-3 spacecraft. Its scientific goals are the mapping of lunar regolith and detection of subsurface geologic structures. This paper describes the goals of the mission, as well as the basic principles, design, composition and achievements of the LPR. Finally, experiments on a glacier and the lunar surface are analyzed.

A high-resolution miniature spectrometer has been demonstrated by utilizing a 128-channel integrated filter array, fabricated by using the combinatorial deposition technique, as a dispersive component whose passbands range from 722.0 to 880.0 nm with a bandwidth (or spectral resolution) from 1.7 to 3.8 nm and an average channel interval of 1.2 nm. The miniature spectrometer is smaller than 1 cm3 without any moving parts. This kind of miniature spectrometer has the advantages of very low payload, high resolution, and high reliability simultaneously, which are especially urgently needed for space applications.

The strong coupling between excitons and Fabry-Pérot (F-P) cavity modes in tungsten sulfide (WS₂) thin layers was studied. By using home-made micro-reflectance spectroscopic technique, we observed the anti-crossing behavior between cavity mode and excitons with flake's thickness dependence. Giant Rabi splitting of ~270 meV for A exciton and ~780 meV for B exciton were obtained from the fitting of the cavity polariton dispersions by use of the coupled oscillators model.