DMO by the Huygens‐Fresnel diffraction integral

1993 ◽  
Author(s):  
Vigen Ohanian
Keyword(s):  
Fresnel Diffraction ◽  
Diffraction Integral

scholarly journals Focusing properties of an axicon pair

1993 ◽  
Vol 71 (1-2) ◽  
pp. 70-78 ◽  
Author(s):  
Marc Couture ◽  
Michel Piché
Keyword(s):  
Stationary Phase ◽  
Numerical Method ◽  
Gaussian Beam ◽  
Fresnel Diffraction ◽  
Optical Systems ◽  
Phase Method ◽  
Stationary Phase Method ◽  
Diffraction Integral ◽  
Peak Intensity ◽  
Focusing Properties

The focusing properties of a so-called reflaxicon (a combination of a diverging and a converging axicon) are studied both theoretically and experimentally. Calculations of intensity distributions produced by this system are made by evaluating the Kirchhoff–Fresnel diffraction integral, first by means of an approximate technique, the stationary phase method, then by a more exact numerical method. The calculations are presented for various planes along the axis of the axicons. The effects of the presence of the supporting mount of the axicons and of some important misalignments of the system on the distributions is also investigated. Experimental results of actual intensity distributions produced by focusing a near-fundamental Gaussian beam by such a system are also presented and are seen to be in fair agreement with numerical calculations. Such calculations would be valuable in many applications for predicting important characteristics (e.g., peak intensity, length of the focal line, degree of asymmetry) of the intensity distributions formed by optical systems containing an axicon pair as the focusing component.

scholarly journals Do We Manipulate Photons or Diffractive EM Waves to Generate Structured Light?

2020 ◽  
Author(s):  
ChandraSekhar Roychoudhuri
Keyword(s):  
Angular Momentum ◽  
Structured Light ◽  
Fresnel Diffraction ◽  
Instrument Design ◽  
Initial Moment ◽  
Optical Instrument ◽  
Wave Fronts ◽  
Diffraction Integral ◽  
Propagation Of Light ◽  
Quantum Transitions

In the domain of light emissions, quantum mechanics has been an immensely successful guiding tool for us. In the propagation of light and optical instrument design, Huygens-Fresnel diffraction integral (HFDI) (or its advanced versions) and Maxwell’s wave equation are continuing to be the essential guiding tools for optical scientists and engineers. In fact, most branches of optical science and engineering, like optical instrument design, image processing, Fourier optics, Holography, etc., cannot exist without using the foundational postulates behind the Huygens-Fresnel diffraction integral. Further, the field of structured light is also growing where phases and the state of polarizations are manipulated usually with suitable classical macro-devices to create wave fronts that restructured through light-matter interactions through these devices. Mathematical modeling of generating such complex wave fronts generally follows classical concepts and classical macro tools of physical optics. Some of these complex light beams can impart mechanical angular momentum and spin-like properties to material particles inserted inside these structured beams because of their electromagnetic dipolar properties and/or structural anisotropy. Does that mean these newly structured beams have acquired new quantum properties without being generated through quantum devices and quantum transitions? In this chapter, we bridge the classical and quantum formalism by defining a hybrid photon (HP). HP is a quantum of energy, hν, at the initial moment of emission. It then immediately evolves into a classical time-finite wave packet, still transporting the original energy, hν, with a classical carrier frequency ν (oscillation of the E-vector). This chapter will raise enquiring questions whether all these observed “quantum-like” behaviors are manifestations of the joint properties of interacting material particles with classical EM waves or are causal implications of the existence of propagation of “indivisible light quanta” with exotic properties like spin, angular momentum, etc.

Generalized Fresnel diffraction integral and its applications

2000 ◽  
Vol 9 (2) ◽  
pp. 119-123 ◽  
Author(s):  
Yang Jun ◽  
Fan Dian-yuan ◽  
Wang Shi-ji ◽  
Gu Yuan
Keyword(s):  
Fresnel Diffraction ◽  
Diffraction Integral

Many waves I: Fresnel and Fraunhofer

Optics f2f ◽  
2018 ◽  
pp. 71-90
Author(s):  
Charles S. Adams ◽  
Ifan G. Hughes
Keyword(s):  
Fresnel Diffraction ◽  
Circular Aperture ◽  
Fraunhofer Diffraction ◽  
Diffraction Integral

This chapter considers the sum of many curved waves in the forms of the Fresnel diffraction integral. First the case of diffraction by a circular aperture is analysed, followed by two regimes where Fresnel diffraction reduces to the case known as Fraunhofer diffraction.

scholarly journals Comparative Analysis of Some Schell-Model Beams Propagating Through Turbulent Atmosphere

2021 ◽  
Author(s):  
Salma Chib ◽  
Latifa Dalil-Essakali ◽  
Abdelmajid Belafhal
Keyword(s):  
Comparative Analysis ◽  
Spectral Density ◽  
Optical System ◽  
Turbulent Atmosphere ◽  
Fresnel Diffraction ◽  
Diffraction Integral ◽  
Receiver Plane ◽  
Different Shapes ◽  
Abcd Optical System ◽  
Analytical Expressions

Abstract In this paper, we investigate a comparative analysis of some Generalized Laguerre-Gaussian Schell-model beams through a paraxial ABCD optical system in a turbulent atmosphere. Based on the extended Huygens-Fresnel diffraction integral, analytical expressions for the spectral density in the receiver plane of the studied beams are derived in detail. By studying the effects of the source coherence parameters and the atmospheric turbulence strength, the numerical results indicate that the profile of these Schell-model beams takes different shapes during their propagation.

Observation of Phase Contrast Images in STEM and CTEM Modes by Using 100 kV Field Emission Electron Gun

1974 ◽  
Vol 32 ◽  
pp. 390-391
Author(s):  
Y. Harada ◽  
T. Goto ◽  
H. Koike ◽  
T. Someya
Keyword(s):  
Field Emission ◽  
Phase Contrast ◽  
Image Formation ◽  
Fresnel Diffraction ◽  
Experimental Results ◽  
Electron Gun ◽  
Scanning Microscopy ◽  
Emission Electron ◽  
Lattice Images

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.

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