We propose the use of two-dimensional (2D) photonic crystals (PhCs) with engineered defects for the generation of an arbitrary-profile beam from a focused input beam. The cylindrical harmonics expansion of complex-source beams is derived and used to compute the scattered wave function of a 2D PhC via the multiple scattering method. The beam shaping problem is then solved using a genetic algorithm. We illustrate our procedure by generating different orders of Hermite-Gauss profiles, while maintaining reasonable losses and tolerance to variations in the input beam and the slab refractive index.
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http://dx.doi.org/10.1364/JOSAA.29.002673 | DOI Listing |
LiNbO domain structures have been widely applied in nonlinear beam shaping, quantum light generation, and nonvolatile ferroelectric memory. The recent developments in nanoscale domain engineering techniques make it possible to fabricate sub-diffracted nanodomains in LiNbO crystal for high-speed modulation and high-capacity storage. However, it still lacks a feasible and efficient way to characterize these nanoscale domains.
View Article and Find Full Text PDFWe present the first, to our knowledge, metasurface holographic display method with exceptional fidelity and minimal edge noise, based on highly uniform flat-top light generated by a digital micromirror device (DMD). Based on the error-diffusion algorithm and iterative refinement process, the amplitude distribution of the initial Gaussian light was dynamically closed-loop modulated, and the standard difference of the intensity of the 3 mm diameter center flat-top beam was reduced to less than 3.4%.
View Article and Find Full Text PDFJ Prosthet Dent
January 2025
Undergraduate student, School of Mechanical Engineering, Shandong University of Technology, Zibo, PR China.
Statement Of Problem: Infrared radiation heating (IRH) technology has been innovatively applied to the annealing of selective laser melted (SLM) cobalt chromium (Co-Cr) frameworks. However, previous studies have not reported the effects of IRH on the warping deformation and mechanical properties of these frameworks.
Purpose: The purpose of this in vitro study was to investigate the effects of IRH on the warping deformation and mechanical properties of dental SLM Co-Cr alloy and to evaluate its potential applications in dental restorations.
Biomed Phys Eng Express
January 2025
Physics Department, University at Albany, 1400 Washington Ave, Albany, New York, 12222-0100, UNITED STATES.
Conventional x-ray radiography relies on attenuation differences in the object, which often results in poor contrast in soft tissues. X-ray phase imaging has the potential to produce higher contrast but can be difficult to utilize. Instead of grating-based techniques, analyzer-based imaging, also known as diffraction enhanced imaging (DEI), uses a monochromator crystal with an analyzer crystal after the object.
View Article and Find Full Text PDFAppl Radiat Isot
January 2025
Particle Radiation Oncology Research Center, Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2-Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka, 590-0494, Japan.
Recent decades have seen the development of accelerator neutron sources suitable for installation in a hospital setting. Numerous challenges have been faced and solved to deliver technology which continues to transform the field of BNCT. This paper begins by briefly reviewing the technologies which are currently, or soon will be, in clinical use.
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