We propose a possible generalization of the waist plane for a two-dimensional astigmatic Gaussian beam as a plane of minimal spot area of the beam during propagation. It is shown that the defocusing component of the beam phase vanishes in this plane. Some examples of astigmatic Gaussian beams and corresponding area waist planes are presented and discussed.
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Article Synopsis
- Astigmatic unitary transformations enable the smooth transition between various states of paraxial Gaussian beams, specifically Hermite-Laguerre-Gaussian (HLG) modes, on a modal sphere.
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A low-threshold efficient setup for CW wavelength versatile vortex generation is proposed. The intracavity optical parametric oscillator is utilized for low-threshold operation. By using the pump-wave off-axis pumping for the signal-wave oscillator, high-order Hermite-Gaussian modes at the eye-safe region can be obtained, which can further generate a vortex via an astigmatism mode converter.
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Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
To determine the distribution of keratometry and corneal astigmatism (CA) and their association with demographic factors, systemic parameters, anthropometric measures, ocular biometric indices, and refractive errors in people aged 60 years and above. In this cross-sectional study, 160 clusters were randomly selected from Tehran city (Iran) using the multi-stage cluster sampling method. All participants underwent optometric examinations including testing uncorrected and best-corrected distance visual acuity, non-cycloplegic autorefraction, and subjective refraction.
View Article and Find Full Text PDFSpatiotemporal optical vortices with controllable radial and azimuthal quantum numbers.
Nat Commun
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School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai, China.
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- This research investigates optical spatiotemporal vortices with transverse photon orbital angular momentum, focusing on spatiotemporal Laguerre-Gaussian (STLG) wavepackets that display unique topological features.
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Morphological Features Among Gaussian, Sagittal, and Tangential Curvature Maps in Normal and Keratoconus Eyes Using Anterior Segment Optical Coherence Tomography.
Eye Contact Lens
July 2024
Research Department (M.A.H., J.E.S., J.L., J.C., L.I.), Oftalmosalud Institute of Eyes, Lima, Perú; Department of Statistics, Demography, Humanities and Social Sciences (J.C.), Universidad Peruana Cayetano Heredia, Lima, Perú; Department of Ophthalmology (P.S.B.), Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA; and San Fernando School of Medicine (L.I.), Universidad Nacional Mayor de San Marcos, Lima, Perú.
Purpose: To investigate and compare the morphological features and differences among Gaussian, Sagittal, and Tangential anterior corneal curvature maps obtained with an anterior segment optical coherence tomographer combined with a Placido disc MS-39 device in keratoconus (KC) and normal eyes.
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