Related Experiment Video
Updated: Jun 12, 2026
05:10
Measuring the Behavioral Effects of Intraocular Scatter
Published on: February 18, 2021
Diffraction patterns in the shadows of disks and obstacles.
Applied Optics
|June 10, 2010
Summary
This study compares Fresnel diffraction patterns for circular disks and square obstacles, noting unique features for squares. Rigorous electromagnetic calculations show minimal differences between disk and sphere diffraction in the Fresnel region.
Area of Science:
- Optics and Electromagnetism
- Wave Phenomena
Background:
- Diffraction patterns are crucial for understanding wave behavior.
- Previous studies often rely on approximations like Fresnel diffraction.
- Comparing different obstacle shapes provides insights into wave scattering.
Purpose of the Study:
- To compare Fresnel diffraction patterns of circular disks and square obstacles.
- To evaluate the on-axis field strength for these shapes.
- To contrast rigorous electromagnetic field calculations with Fresnel approximations.
Main Methods:
- Photographic analysis of diffraction patterns.
- Precise calculation of electric and magnetic fields without Fresnel approximation.
- Comparison with rigorous electromagnetic results for a metal sphere.
Main Results:
- Observed unique diffraction features for square obstacles.
- Calculated electric and magnetic fields behind a conducting circular disk.
- Found only slight differences between disk and sphere diffraction in the Fresnel region.
Conclusions:
- Square obstacles exhibit distinct diffraction patterns compared to circular disks.
- Rigorous electromagnetic analysis confirms the validity of Fresnel approximations in certain regions.
- The study provides a detailed comparison of diffraction phenomena for different geometries.
Related Concept Videos
02:18Interference and Diffraction
Interference is a characteristic phenomenon exhibited by waves. When two electromagnetic waves interact with their peaks and troughs coinciding, a resulting wave with enhanced amplitude is produced. This is known as constructive interference. In this case, the two waves interacting are in phase with each other.
02:18X-ray Crystallography
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
01:10X-ray Diffraction of Biological Samples
X-ray diffraction or XRD is an analytical tool that utilizes X-rays to study ordered structures such as crystalline organic and inorganic samples, polycrystalline materials, proteins, carbohydrates, and drugs.
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal crystal...
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal crystal...
01:29Determination of Crystal Structures
In the late 1800s, the revelation that light extended beyond visible wavelengths led to the discovery of X-rays by Wilhelm Roentgen. Recognized as high-energy electromagnetic radiation with short wavelengths, X-rays prompted exploration into their interaction with crystals. Max von Laue proposed in 1912 that the periodic arrangement of atoms, ions, or molecules in crystals would cause them to diffract X-rays, a hypothesis confirmed through experiments with copper sulfate and zinc sulfide...
01:26Phase Contrast and Differential Interference Contrast Microscopy
Phase-Contrast Microscopes
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
01:23Electric Field of a Charged Disk
The simplest case of a surface charge distribution is the uniformly charged disk. Calculating its electric field also helps us calculate the electric field of a large plane of charge.
The system's symmetry is in the cylindrical directions across the plane of the charge. As a result, the electric fields created by various surface charge elements nullify each other in the direction parallel to the surface. Thereby, the resulting electric field is perpendicular to the plane. Since the disk is...
The system's symmetry is in the cylindrical directions across the plane of the charge. As a result, the electric fields created by various surface charge elements nullify each other in the direction parallel to the surface. Thereby, the resulting electric field is perpendicular to the plane. Since the disk is...