Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Calculation of Electric Flux01:25

Calculation of Electric Flux

Consider the electric field of an oppositely charged, parallel-plate system and an imaginary box between those plates. Let the bottom face of the box be ABCD, and the top face be FGHK. The electric field between the plates is uniform and points from the positive plate toward the negative plate. The calculation of this field's flux through the box's various faces shows that the net flux through the box is zero. Why does the flux cancel out here?
Sight Distance in a Vertical Curve01:29

Sight Distance in a Vertical Curve

Sight distance on vertical curves is critical in roadway design. It ensures drivers can see far enough ahead to identify and respond to hazards effectively. This directly impacts safety, driver comfort, and the overall efficiency of the transportation network.Vertical curves are classified into crest and sag curves based on their geometry. For crest curves, sight distance is determined by the line of sight between a driver's eye and a small object on the road's surface. Design parameters for...
Gauss's Law: Problem-Solving01:10

Gauss's Law: Problem-Solving

Gauss's law helps determine electric fields even though the law is not directly about electric fields but electric flux. In situations with certain symmetries (spherical, cylindrical, or planar) in the charge distribution, the electric field can be deduced based on the knowledge of the electric flux. In these systems, we can find a Gaussian surface S over which the electric field has a constant magnitude. Furthermore, suppose the electric field is parallel (or antiparallel) to the area vector...
Super-resolution Fluorescence Microscopy01:37

Super-resolution Fluorescence Microscopy

Super-resolution fluorescence microscopy (SRFM) provides a better resolution than conventional fluorescence microscopy by reducing the point spread function (PSF). PSF is the light intensity distribution from a point that causes it to appear blurred. Due to PSF, each fluorescing point appears bigger than its actual size, and it is the PSF interference of nearby fluorophores that causes the blurred image. Various approaches to achieving higher resolution through SRFM have recently been developed.
Electric Flux01:15

Electric Flux

The concept of flux describes how much of something goes through a given area. More formally, it is the dot product of a vector field within an area. For a better understanding, consider an open rectangular surface with a small area that is placed in a uniform electric field. The larger the area, the more field lines go through it and, hence, the greater the flux; similarly, the stronger the electric field (represented by a greater density of lines), the greater the flux. On the other hand, if...
Influence of Earth's Curvature and Atmospheric Refraction on Leveling01:26

Influence of Earth's Curvature and Atmospheric Refraction on Leveling

During leveling, the Earth's curvature and atmospheric refraction introduce deviations in the line of sight from a true horizontal reference. When the line of sight is leveled, it remains perpendicular to the plumb line only at a single point. Beyond this, it deviates due to the Earth’s curvature, represented by the correction C. For a sight distance D, the deviation can be derived using the relationship:This relationship shows that the deviation increases quadratically with distance. Over a...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Sympathetic neurons exacerbate atherosclerosis by modulating macrophage function via the NPY/Y1R axis.

Atherosclerosis·2026
Same author

Long-Term Inorganic Nitrogen Fertilization Drives a Trade-Off in the Soybean Symbiotic Network From Low-Loss Fixation to High-Loss Metabolism.

Molecular ecology·2026
Same author

RTS-SLAM: A Trajectory Consistency-Driven Multi-Constraint Dynamic Feature-Rejection Method for Visual SLAM in Dynamic Environments.

Sensors (Basel, Switzerland)·2026
Same author

Research trends and emerging themes in abdominal aortic calcification: a 2005-2025 bibliometric analysis.

Journal of cardiothoracic surgery·2026
Same author

Qiling Hushen Formula Ameliorates Type 2 Diabetic Kidney Disease via Gut-Kidney Axis Restoration and TLR4/NF-κB/NLRP3 Suppression.

Journal of diabetes research·2026
Same author

Correction: Neoadjuvant therapy with cadonilimab in a patient with MSI-H/dMMR colorectal cancer: a case report.

Frontiers in oncology·2026
Same journal

Multifunctional reconfigurable terahertz metasurface based on vanadium dioxide phase transition: achieving broadband absorption and efficient polarization conversion.

Applied optics·2026
Same journal

High-Q-factor electromagnetically induced transparency utilizing quasi-bound states in the continuum in an all-dielectric terahertz metasurface.

Applied optics·2026
Same journal

Automated stitching interferometry for high-precision metrology of X-ray mirrors.

Applied optics·2026
Same journal

Experimental demonstration of an approach to designing a metal-dielectric DBR resonant cavity structure.

Applied optics·2026
Same journal

High-precision wavefront reconstruction from a single-shot interferogram using a physics-driven hybrid feature calibration network.

Applied optics·2026
Same journal

Ultra-high-Q Fano resonance based on coupled topological corner states in Kagome photonic crystals.

Applied optics·2026
See all related articles

Related Experiment Video

Updated: May 13, 2026

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics
09:00

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics

Published on: October 27, 2017

Far-field distance for surface light source with different luminous area.

Xianming Liu1, Wentao Cai, Xiaohua Lei

  • 1Key Lab for Optoelectronic Technology & Systems of Ministry of Education, Chongqing University, Chongqing, China. xianming65@163.com

Applied Optics
|March 13, 2013
PubMed
Summary
This summary is machine-generated.

The classical five times rule for light source far-field conditions is not universally applicable. New far-field conditions are deduced for continuous surface light sources, revealing limitations for certain shapes.

More Related Videos

Measuring the Behavioral Effects of Intraocular Scatter
05:10

Measuring the Behavioral Effects of Intraocular Scatter

Published on: February 18, 2021

Measuring Spatially- and Directionally-varying Light Scattering from Biological Material
11:57

Measuring Spatially- and Directionally-varying Light Scattering from Biological Material

Published on: May 20, 2013

Related Experiment Videos

Last Updated: May 13, 2026

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics
09:00

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics

Published on: October 27, 2017

Measuring the Behavioral Effects of Intraocular Scatter
05:10

Measuring the Behavioral Effects of Intraocular Scatter

Published on: February 18, 2021

Measuring Spatially- and Directionally-varying Light Scattering from Biological Material
11:57

Measuring Spatially- and Directionally-varying Light Scattering from Biological Material

Published on: May 20, 2013

Area of Science:

  • Optics and Photonics
  • Illumination Engineering
  • Radiometry

Background:

  • Lighting design often relies on far-field approximations of light sources.
  • Accurate far-field assessment is crucial for simulating light sources as point sources.
  • Current far-field rules may not adequately address the complexity of surface light sources.

Purpose of the Study:

  • To deduce and calculate the far-field conditions for surface light sources with continuous luminous areas.
  • To evaluate the applicability of the classical far-field rule to various flat and curved surface light source geometries.
  • To provide accurate far-field distance criteria for improved lighting design and measurement.

Main Methods:

  • Deduction of mathematical expressions for far-field conditions specific to continuous surface light sources.
  • Calculation of relative far-field distances for geometries including round, rectangular, annular, hemispherical, and semi-cylindrical sources.
  • Comparative analysis of calculated far-field distances against the classical five times rule.

Main Results:

  • The classical five times rule was found to be inapplicable for hemispherical, arc-shaped semi-cylindrical, and narrow annular surface light sources.
  • Specific far-field distance criteria were determined for different surface light source shapes.
  • The study highlights the necessity of shape-specific far-field analysis for accurate lighting simulations.

Conclusions:

  • The generalized far-field conditions derived are essential for accurate lighting design involving surface sources.
  • Relying solely on the classical five times rule can lead to significant errors in far-field approximation for certain geometries.
  • This research provides a more refined understanding of far-field behavior for diverse surface light sources.