Pattern self-referenced single-pixel computational holographic imaging

We propose pattern self-referenced single-pixel common-path holography(PSSCH),which can be realized using either the digital-micromirror-device(DMD)based off-axis scheme or the DMD-based phaseshifting approach,sharing the same experimental setup,to do wavefront reconstructions.In this method,each modulation pattern is elaborately encoded to be utilized to not only sample the target wavefront but also to dynamically introduce the reference light for single-pixel common-path holographic detection.As such,it does not need to intentionally introduce a static reference light,resulting in it making full use of the pixel resolution of the modulation patterns and suppressing dynamically varying noises.Experimental demonstrations show that the proposed method can not only obtain a larger field of view than the peripheral-referenced approach but also achieve a higher imaging resolution than the checkerboardreferenced approach.The phase-shifting-based PSSCH performs better than the off-axis-based PSSCH on imaging fidelity,while the imaging speed of the latter is several times faster.Further,we demonstrate our method to do wavefront imaging of a biological sample as well as to do phase detection of a physical lens.The experimental results suggest its effectiveness in applications.

High detectivity photodetectors based on perovskite nanowires with suppressed surface defects

Solution-processable,single-crystalline perovskite nanowires are ideal candidates for developing low-cost photodetectors,but their detectivities are limited due to a high level of unintentional defects.Through the surfaceinitiated solution-growth method,we fabricated high-quality,single-crystalline,defects-suppressed MAPbI_(3) nanowires,which possess atomically smooth side surfaces with a surface roughness of 0.27 nm,corresponding to a carrier lifetime of 112.9 ns.By forming ohmic MAPbI_(3)∕Au contacts through the dry contact method,highperformance metal–semiconductor–metal photodetectors have been demonstrated with a record large linear dynamic range of 157 dB along with a record high detectivity of 1.2×10^(14) Jones at an illumination power density of 5.5 nW∕cm^(2).Such superior photodetector performance metrics are attributed to,first,the defects-suppressed property of the as-grown MAPbI_(3) nanowires,which leads to a quite low noise current in the dark,and second,the ohmic contact between MAPbI_(3) and Au interfaces,which gives rise to an improved responsivity compared with the Schottky contact counterpart.The realized high-performance MAPbI_(3) nanowire photodetector advances the development of low-cost photodetectors and has potential applications in weak-signal photodetection.