Factors that govern the diffraction of electromagnetic waves

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Discussion Overview

The discussion revolves around the factors that govern the diffraction of electromagnetic waves, particularly focusing on the differences in diffraction behavior between ordinary light and laser light. Participants explore concepts related to coherence and its relationship to diffraction, as well as the physical dimensions involved in the diffraction process.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that the monochromatic character of laser light may influence its diffraction properties compared to ordinary light.
  • One participant explains diffraction as the scattering of waves when passing through openings, using an analogy with water flow through a narrowed tube.
  • Another participant introduces the concept of coherence, distinguishing between spatial and temporal coherence, and suggests that coherent light, like that from lasers, remains more ordered and less prone to scattering.
  • There is a challenge to the idea that ordinary light diffracts more than laser light, with a participant arguing that diffraction and coherence are fundamentally different concepts.
  • One participant notes that diffraction occurs when radiation interacts with matter that has dimensions similar to its wavelength.
  • An analogy involving ping-pong balls is used to illustrate coherence, contrasting coherent and incoherent behavior.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between coherence and diffraction, with some agreeing that coherence affects diffraction behavior while others question the initial premise regarding ordinary light's diffraction compared to laser light. The discussion remains unresolved regarding the precise nature of these relationships.

Contextual Notes

Participants have not fully defined the terms involved, and there are missing assumptions regarding the conditions under which diffraction occurs. The discussion also reflects varying levels of understanding about coherence and its implications for diffraction.

sid_galt
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What are the factors that govern the diffraction of electromagnetic waves.

Why is it that ordinary light diffracts so much while laser is so precise. Does it have to do something with the monochromatic character of laser?
 
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Perhaps you should explain to us what you undersand of defraction?
 
sid_galt said:
What are the factors that govern the diffraction of electromagnetic waves.

Why is it that ordinary light diffracts so much while laser is so precise. Does it have to do something with the monochromatic character of laser?

Diffraction basically means the scattering of some wave when passing through some opening. Just look at what would happen if you would narrow down the opening of some tube in which water flows. I think you can imagine the result. It happens to all waves but indeed the scattering is not the same for all waves. The reason why a laserbeam stays together is the fact that lasers are coherent light. There are two types of coherency : spatial and time-like coherence. For example let's look at a wave that consists out of two subwaves. If you would look at some point on each subwave, you will see that the distances between those two points (one point on each subwave) does not alter when the wave propagates through space and time. One subwave does not run away from the other subwave, they stay together. This kind of wave is very ordened and no subwave will scatter off.


marlon

check out my journal for more info on coherent light
https://www.physicsforums.com/journal.php?s=&action=view&journalid=13790&perpage=10&page=4

just look at the "for nanotechnology and micro-electronics lovers"-entry
 
Last edited by a moderator:
sid_galt said:
What are the factors that govern the diffraction of electromagnetic waves.

Why is it that ordinary light diffracts so much while laser is so precise. Does it have to do something with the monochromatic character of laser?

Not sure what you have in mind when you say ordinary light diffracts more than a laser. Seems like you mix diffraction and coherence. Completely different things.

Diffraction happens when a radiation hits matter with similar physical dimensions as its wavelength.

Coherence is what marlon said. A more elementary way to see it is by dropping a box of ping-pong balls. If they all bounce together, they are coherent. If they're a mess, they are incoherent. If they bounce together at first, and after a while, they're a mess, there is a coherence time constant, which is the case with actual lasers.
 
Thank you marlon and Gonzolo, that helped a lot. I was mixing coherence and diffraction.
 

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