Directions of rectification and photocurrent in a ferroelectric BiFeO3 crystal can be switched by applying high‐voltage pulses at room temperature. The switching is highly repeatable though cycling and also stable with time. This switchable photocurrent and diode effect results from the combination of polarization flipping and electromigration of oxygen vacancies.

We report on the anisotropic optical properties of single-crystal tin monosulfide (SnS). The components e a , e b , and e c of the pseudodielectric-function tensor hei ¼ he 1 i þ ihe 2 i spectra are taken from 0.73 to 6.45 eV by spectroscopic ellipsometry. The measured hei spectra are in a good agreement with the results of the calculated dielectric response from hybrid density functional theory. The hei spectra show the direct band-gap onset and a total of eight above-band-gap optical structures that are associated with the interband-transition critical points (CPs). We obtain accurate CP energies by fitting analytic CP expressions to second-energy-derivatives of the hei data. Their probable electronic origins and implications for photovoltaic applications are discussed. V C 2014 AIP Publishing LLC. [http://dx.

Spectroscopic ellipsometry was used to determine the pseudodielectric function <ε> = <ε 1 > + i<ε 2 > spectrum of a natural single crystal of iron pyrite (cubic FeS 2 ) from 0.5 to 4.5 eV with the sample at 77 K.The <ε> spectrum exhibits several pronounced optical features associated with the interband critical points (CPs). Accurate CP energies are obtained by fitting standard lineshapes to second-energyderivatives of the <ε> data. The electronic origins of the six observed CP features are identified through density functional theory (DFT) calculations and momentum matrix analyses. a) Author to whom correspondence should be addressed. Electronic mail: sukgeun.choi@nrel.gov.2

We present a first attempt for stereoscopic image super-resolution (SR) for recovering high-resolution details while preserving stereo-consistency between stereoscopic image pair. The most challenging issue in the stereoscopic SR is that the texture details should be consistent for corresponding pixels in stereoscopic SR image pair. However, existing stereo SR methods cannot maintain the stereo-consistency, thus causing 3D fatigue to the viewers. To address this issue, in this paper, we propose a self and parallax attention mechanism (SPAM) to aggregate the information from its own image and the counterpart stereo image simultaneously, thus reconstructing high-quality stereoscopic SR image pairs. Moreover, we design an efficient network architecture and effective loss functions to enforce stereo-consistency constraint. Finally, experimental results demonstrate the superiority of our method over state-of-the-art SR methods in terms of both quantitative metrics and qualitative visual quality while maintaining stereo-consistency between stereoscopic image pair.

Polarization-sensitive photodetection has attracted considerable attention as an emerging technology for future optoelectronic applications such as three-dimensional (3D) imaging, quantum optics, and encryption. However, traditional photodetectors based on Si or III−V InGaAs semiconductors cannot directly detect polarized light without additional optical components. Herein, we demonstrate a selfpowered linear-polarization-sensitive near-infrared (NIR) photodetector using a two-dimensional WSe 2 /ReSe 2 van der Waals heterostructure. The WSe 2 /ReSe 2 heterojunction photodiode with semivertical geometry exhibits excellent performance: an ideality factor of 1.67, a broad spectral photoresponse of 405− 980 nm with a significant photovoltaic effect, outstanding linearity with a linear dynamic range wider than 100 dB, and rapid photoswitching behavior with a cutoff frequency up to 100 kHz. Strongly polarized excitonic transitions around the band edge in ReSe 2 lead to significant 980 nm NIR linear-polarization-dependent photocurrent. This linear polarization sensitivity remains stable even after exposure to air for longer than five months. Furthermore, by leveraging the NIR (980 nm)-selective linear polarization detection of this photodiode under photovoltaic operation, we demonstrate digital incoherent holographic 3D imaging.