We compare the iterative angular spectrum (IAS) and the optimal rotation angle (ORA) methods in designing two-dimensional finite aperture diffractive optical elements (FADOEs) used as beamfanners. The transfer functions of both methods are compared analytically in the spatial frequency domain. We have designed several structures of 1-to-4 and 1-to-6 beamfanners to investigate the differences in the performance of the beamfanners designed by ORA method for near field operation. Using the three-dimensional finite difference time-domain (3-D FDTD) method with perfect matched layer (PML) absorbing boundary condition (ABC), the diffraction efficiency is calculated for each designed FADOE and the corresponding values are compared.
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http://dx.doi.org/10.1364/oe.17.014825 | DOI Listing |
Phys Med Biol
January 2025
Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology (QST), 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
J Bone Joint Surg Am
December 2024
Pediatric Orthopaedic Unit, Pediatric Surgery Service, Geneva University Hospitals, Geneva, Switzerland.
Background: Transphyseal hematogenous osteomyelitis (THO) is a common infectious condition, being present in 25% of patients with hematogenous osteomyelitis. A large proportion of pediatric hematogenous osteomyelitis infections can spread through the growth cartilage and therefore may be potentially responsible for growth disorders, leading to limb-length discrepancy or angular deformities. The purpose of the present study was to identify both the prevalence of complications caused by transphyseal osteomyelitis and factors influencing their occurrence.
View Article and Find Full Text PDFPhotoacoustics
December 2024
Ministry-of-Education Key Laboratory of Modern Acoustics, Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
To correct the refraction aberration induced by the skull in photoacoustic imaging, a method for phase distortion compensation is proposed based on the angular spectrum theory with the aid of ultrasonic signals. This method first updates the speed of sound distribution by iteratively performing aberration correction in the ultrasonic reconstruction. Then the speed of sound distribution obtained with ultrasound-assisted serves as prior knowledge to address phase distortion compensation by adjusting the phase shift factor of the wavefront in different media.
View Article and Find Full Text PDFZhonghua Kou Qiang Yi Xue Za Zhi
December 2024
Institute of Medical Technology, Peking University Health Science Center, Beijing100191, China.
To explore the impact of digital technology in constructing a three-dimensional (3D) symmetry reference plane (SRP) for esthetic restoration of anterior teeth and to evaluate its clinical applicability. A cross-sectional study was conducted from February to May 2024, involving 20 patients [11 males and 9 females, aged (36.8±11.
View Article and Find Full Text PDFLight field imaging can simultaneously record spatial and angular information of light signals to provide various computational imaging functions. However, traditional microlens array-based light field cameras usually suffer from a trade-off between spatial and angular resolutions. In contrast, focal scanning light field imaging (FSLFI) can digitally modulate an incident light field through an image stack captured at different focal planes and then utilize the transport-of-intensity property to computationally recover the full-resolution light field.
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