Binary photoresponse characteristics can help realize optical signal processing and logic operations. UV photodetectors (PDs) with SnS x nanoflakes and TiO2 nanorod arrays (NRs) show a novel binary photoswitching behavior (change in current from positive to negative) by manipulating the light wavelength without an external power source, utilizing the interfacial recombination of the photogenerated carriers in the type-I SnS x /TiO2 heterojunctions. The enhanced responsivity (R*), detectivity (D* ), and fast photoresponse time for self-powered SnS x /TiO2PDs can be achieved by adjusting the phase ratio of SnS and SnS2 nanoflakes. The binary photoswitching in the self-powered UV PDs can be applied in the encrypted optical signal processing and imaging in some special conditions without external bias.

Reducing carrier trapping in the grain boundary of semiconductor materials can improve the carrier transport. Adding Na2EDTA in electrolyte can regulate the growth process of Cu2O thin films electrochemical deposited...

Abstract-This paper presents a new unequally spaced and excited resonant slotted-waveguide antenna array. It is realized by employing an improved resonant-slot coupled cavity chain composite right/lefthanded (CRLH) waveguide. As the CRLH waveguide works at the infinite wavelength frequency, all the slot elements along the waveguide wall are excited in-phase. Thus both the element spacings and excitation amplitudes are introduced into the synthesis to realize a resonant slotted-waveguide antenna array. A seven-element unequally spaced and excited antenna array which generates pencil beam is synthesized, simulated and fabricated.The results show, with comparison to the equally spaced but unequally excited resonant slotted-waveguide antenna array, the proposed unequally spaced and excited array produces a lower peak sidelobe level (PSLL).

We propose and demonstrate that a dark spot can be generated by a radially polarized beam with a first-order vortex after phase modulation by an optimal binary phase element. The distance between two mainlobe intensity peaks along the radial direction is 0.62λ on the focal plane. The proposed system is easy to implement in practice and has low energy loss, since it uses phase-only modulation. Then, the fluorescent spot is calculated for stimulated emission depletion microscopy when a radially polarized beam works as the pump beam. The FWHM of the fluorescent spot can achieve 0.008λ for a saturated case. This is much smaller than that achieved using a circular polarized vortex erase beam (0.0422λ) or an azimuthally polarized erase beam with optimizing amplitude-phase modulation (0.0279λ).

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