Can Two Lasers Overlap and Create a Single Point of Light?

  • Context: High School 
  • Thread starter Thread starter tomc
  • Start date Start date
  • Tags Tags
    Overlapping
Click For Summary

Discussion Overview

The discussion revolves around the possibility of two laser beams crossing to create the illusion of a small point of light in the air. It explores both theoretical and practical aspects, including the conditions necessary for visibility and applications in technology.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that two intersecting laser beams can create the illusion of a point of light, provided there are particles in the air to scatter the light.
  • Others argue that without scattering particles, such as dust, the beams would not be visible from the side, and thus using two lasers would not change this fact.
  • A participant mentions that at the intersection point of two beams, there would be more photons available for scattering than from a single beam, potentially enhancing visibility.
  • Another participant notes that while lasers intersecting in empty space do not affect each other, they can have practical applications in mediums with specific properties, such as in certain 3D display technologies.
  • Examples of 3D displays are provided, including one that uses infrared lasers in a glass cube and another that ionizes air with a powerful laser to create visible light.

Areas of Agreement / Disagreement

Participants express differing views on the visibility of intersecting laser beams, with some supporting the idea that they can create a visible point of light under certain conditions, while others maintain that visibility is not achievable without scattering particles. The discussion remains unresolved regarding the effectiveness of two lasers in creating a visible point of light.

Contextual Notes

The discussion highlights the dependence on environmental conditions, such as the presence of scattering particles, and the limitations of using lasers in empty space versus in specific mediums.

tomc
Messages
1
Reaction score
0
Is it possible two have two beams of light crossing to give the illusion of a small point of light in the air?
 
Science news on Phys.org
No, you can't "see" a laser beam from the side unless the light is being scattered from something (e.g. dust). Using two lasers won't make a difference.
 
tomc said:
Is it possible two have two beams of light crossing to give the illusion of a small point of light in the air?

Yes.
Just like what happens when two searchlight beams cross. Something in the air(dust, water particles, etc...) must of course be present.
In any event, at the point of beam intersection, there are more photons available for scattering than from one beam alone.
 
Two lasers intersecting in empty space won't have any effect on each other. Two lasers intersecting in a medium that has certain illumination-dependent properties is a bit more useful.

Something similar is done in at least two different types of 3D displays. One uses two infrared lasers scanning a glass cube doped with a material that fluoresces visibly when illuminated by both simultaneously. Color can be achieved using different lasers to light up different fluorescent dopants. A block of glass big enough to be a useful display would be both massive and extremely expensive, though.
http://www.3dtl.com/page9.php

Another works in air, and instead of using multiple lasers intersecting at a point, uses a single wide beam focused to a point to ionize the air to the point that it glows. This works in open air, but requires dangerously powerful lasers, and doesn't do color. Something similar is used to "etch" 3D shapes inside a block of glass:
http://www.bathsheba.com/crystal/
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 23 ·
Replies
23
Views
3K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 37 ·
2
Replies
37
Views
5K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 21 ·
Replies
21
Views
4K
  • · Replies 6 ·
Replies
6
Views
1K