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Using the Debye model and existing experimental data of the pyroelectric coefficient of AlN, the temperature dependence of the pyroelectric coefficient as well as the spontaneous polarization of AlN is calculated over a wide temperature range from 0to1000K. The pyroelectric coefficient is proportional to T3 at low temperature and increases acutely from 0 to around 400K, and then increases gently from 400to1000K. It makes AlN uniquely suitable for application in high temperature pyroelectric sensors. The spontaneous polarization of AlN changes a little from 0to1000K, which indicates that the features of III-nitrides based devices will hardly be degraded by the change of the spontaneous polarization.

Various approaches for imaging through scattering layers have been proposed, but very few of them provide depth-resolved images. Here, we propose and experimentally demonstrate an approach for non-invasive depth-resolved imaging of objects hidden behind a scattering medium based on speckle correlations and parallax. The relative intensities of the objects' autocorrelations and the positions of the cross-correlations, both change from different apertures. The reconstruction of objects is achieved by subtraction of the autocorrelations and the conventional Fienup-type iterative phase-retrieval algorithm, and the objects' relative position is retrieved from the relative position of the cross-correlation to the central; moreover, the depth information of objects is decoded by the displacement of the cross-correlations through different apertures. This multi-aperture technique allows sharp imaging of objects with full actual depth information at once.

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