A new scheme for investigating electromagnetically induced grating in four-level cascade-type of 87Rb cold atoms is presented. The novel result indicates that the diffraction efficiency of phase grating is dramatically enhanced due to the presence of an RF-driven field and a diffraction efficiency up to 34% can be obtained. Furthermore, it is found that the frequency detuning of the applied laser fields with the corresponding atomic transition and the interaction length can improve the efficiency of the phase grating in the present atomic model. This work has potential applications in all-optical communication processes.
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http://dx.doi.org/10.1364/AO.54.003484 | DOI Listing |
Acta Crystallogr A Found Adv
March 2025
Department of Physics, Durham University, South Road, Durham, DH1 3LE, United Kingdom.
Bloch waves are often used in dynamical diffraction calculations, such as simulating electron diffraction intensities for crystal structure refinement. However, this approach relies on matrix diagonalization and is therefore computationally expensive for large unit cell crystals. Here Bloch wave theory is re-formulated using the physical optics concepts underpinning the multislice method.
View Article and Find Full Text PDFOptical accordion lattices are routinely used in quantum simulation and quantum computation experiments to tune optical lattice spacings. Here, we present a technique for creating tunable optical lattices using binary-phase transmission gratings. Lattices generated using this technique have high uniformity, contrast, lattice spacing tunability, and power efficiencies.
View Article and Find Full Text PDFThis paper introduces an interferometer for single-shot areal quantitative phase imaging at two wavelengths simultaneously, suitable for use with low coherence sources. It operates in reflection geometry with on-axis illumination, so that it can be conveniently applied to surface texture measurements. The system consists of two identical 4f systems forming the reference and sample arm.
View Article and Find Full Text PDFUtilizing the periodic pixel configuration of the CCD/CMOS imaging sensor as the reference grating and the image of the real grating formed by the lens as the specimen grating, the CCD Moiré method directly outputs amplified Moiré fringes, facilitating high-resolution, full-field deformation measurement. Due to the amplification effect of CCD Moiré, even minor relative rotations of the two gratings can significantly affect Moiré imaging and introduce measurable errors. This paper mainly addresses the imaging and measurement challenges of in-plane rotation in the CCD Moiré method.
View Article and Find Full Text PDFVortex light beams carrying fractional vortices have shown promising applications in many fields such as optical communications, optical encryption, and quantum information processing. Accurate detection of the topological charge of a fractional vortex phase is essential for these applications. In this paper, a simple yet effective method for measuring the fractional topological charge is proposed, which is based on the detection of the orbital angular momentum (OAM) spectrum of a fractional vortex beam diffracted by an angular grating.
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